Decoding device and decoding method, and encoding device and encoding method

ABSTRACT

The present technique relates to a decoding device and a decoding method, and an encoding device and an encoding method, capable of performing encoding and decoding independently in the time direction for each tile. A decoding unit generates a prediction image by performing, for each of tiles, motion compensation of a reference image within a co-located tile based on tile splittable information indicating that decoding is allowed for each of the tiles and motion vector information representing a motion vector used for generating encoded data of a decoding target current image when a picture of the current image is split into the tiles and decoded. The decoding unit decodes the encoded data using the prediction image. The present technique is applicable to a decoding device, for example.

CROSS REFERENCE TO PRIOR APPLICATION

This application is a National Stage Patent Application of PCTInternational Patent Application No. PCT/JP2013/059133 (filed on Mar.27, 2013) under 35 U.S.C. § 371, which claims priority to JapanesePatent Application No. 2012-087869 (filed on Apr. 6, 2012), which areall hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present technique relates to a decoding device and a decodingmethod, and an encoding device and an encoding method, and moreparticularly to a decoding device and a decoding method, and an encodingdevice and an encoding method capable of performing encoding anddecoding independently in the time direction for each tile.

BACKGROUND ART

Currently, standardization of encoding system called High EfficiencyVideo Coding (HEVC) is promoted by Joint Collaboration Team-Video Coding(JCTVC), a joint standardization organization of ITU-T and ISO/IEC,aiming at further improvement of H.264/AVC in encoding efficiency.Concerning HEVC standards, a committee draft as the initial draftversion is issued in February, 2012 (e.g., see Non Patent Literature 1).

According to HEVC standards, a picture can be split into units of tilesor slices for encoding. In decoding an encoded stream split into theseunits and encoded, no correlation exists between the split units in theprocess of creating information about Context-based Adaptive BinaryArithmetic Coding (CABAC), intra prediction modes, quantization values,and the like.

However, according to inter prediction, no restriction is set to motionvectors. In this case, an encoded image of a different tile at adifferent time can be used as a reference image. Accordingly,independent encoding and decoding in the time direction for each tile isnot allowed.

More specifically, as shown in FIG. 1, for example, each of a frame #thaving a Picture Order Count (POC) of t and a frame #t−1 having a POC oft−1 is split into four tiles and inter-predicted, all the encoded imageswithin the four tiles of the frame #t−1 can be determined as possiblereference images for a CU (Coding Unit) of the frame #t.

Accordingly, there is a case when a decoded image 12 within a tile #2having a specific ID (hereinafter referred to as a tile ID) of 2 andcontained in the frame #t−1 is determined as a reference image for a CU11 of a tile #1 having a tile ID of 1 and contained in the frame #t, forexample. In other words, there is a case when a vector which has aninitial point of a CU11 and a terminal point of an area 12A of the frame#t corresponding to the decoded image 12 is detected as a motion vector13. In this case, reference to the decoded image 12 of the tile #2different from the tile #1 containing the CU 11 is needed; therefore,independent encoding and decoding in the time direction for each tile isnot allowed.

Accordingly, a decoding device needs to have a common decoding DecodedPicture Buffer (DPB) which retains decoded images for all tiles.

FIG. 2 is a block diagram showing a constitution example of a decodingdevice of this type.

A decoding device 30 in FIG. 2 is constituted by decoding units 31-1through 31-N, DPB 32-1 through 32-N, and a common DPB 33.

An encoded stream containing split N tiles (N is an arbitrary positivenumber) and encoded for each unit of tiles is inputted to the decodingdevice 30. Encoded data of each tile is supplied to the correspondingdecoding units 31-1 through 31-N.

Each of the decoding units 31-1 through 31-N decodes the encoded data ofthe corresponding tile by using the corresponding image of decodedimages stored in the common DPB 33 for all tiles contained in thecorresponding frame as a reference image.

More specifically, the decoding unit 31-1 decodes encoded data of a tile#1 having a tile ID of 1 using a reference image, and supplies a decodedimage of the tile #1 obtained as a result of the decoding to the DPB32-1. Similarly, the decoding units 31-2 through 31-N decode data of atile #2 having a tile ID of 2, a tile #3 having a tile ID of 3, and upto a tile #N having a tile ID of N using reference images, respectively.Then, the decoding units 31-2 through 31-N supply the decoded images ofthe tile #2, tile #3, and up to tile #N obtained by decoding to the DPB32-2, DPB 32-3, and up to DPB 32-N, respectively.

The DPB 32-1 through 32-N store the decoded images supplied by thecorresponding decoding units 31-1 through 31-N. The DPB 32-1 through32-N supply the stored decoded images to the common DPB 33 and allowthese decoded images to be stored in the common DPB 33.

The common DPB 33 stores the decoded images of the tile #1 through thetile #N at the same time supplied by the DPB 32-1 through 32-N asdecoded images of one frame. The common DPB 33 outputs the storeddecoded images for each unit of frames as decoded results.

In addition, though not shown in the figures, a common DPB needs to beprovided on an encoding device for inter prediction similarly to the DPBon the decoding device 30.

CITATION LIST Non Patent Document

-   Non Patent Document 1: Benjamin Bross, Woo-Jin Han, Jens-Rainer Ohm,    Gary J. Sullivan, Thomas Wiegant, “High efficiency video coding    (HEVC) text specification draft 6” JCTVC-H10003 ver 21, 2012.2.17

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

As described above, according to HEVC standards, no restriction is setto motion vectors in inter prediction. In this case, a decoded image ofa different tile at a different time can be used as a reference image.Accordingly, independent encoding and decoding in the time direction foreach tile is not allowed.

The present technique has been developed in consideration of thesesituations, and is provided as a technique capable of performingencoding and decoding in the time direction independently for each tile.

Solutions to Problems

According to a first aspect of the present technique, there is provideda decoding device, including: a motion compensation unit generating aprediction image by performing, for each of tiles, motion compensationof a reference image within a co-located tile based on tile splittableinformation indicating that decoding is allowed for each of the tilesand motion vector information representing a motion vector used forgenerating encoded data of a decoding target current image when apicture of the current image is split into the tiles and decoded; and adecoding unit decoding the encoded data using the prediction imagegenerated by the motion compensation unit.

The decoding method according to the first aspect of the presenttechnique corresponds to the decoding device according to the firstaspect of the present technique.

According to the first aspect of the present technique, a predictionimage is generated by performing, for each of tiles, motion compensationof a reference image within a co-located tile based on tile splittableinformation indicating that decoding is allowed for each of the tilesand motion vector information representing a motion vector used forgenerating encoded data of a decoding target current image when apicture of the current image is split into the tiles and decoded. Theencoded data is decoded using the prediction image.

According to a second aspect of the present technique, there is providedan encoding device, including: a motion compensation unit generating aprediction image by performing motion compensation of a reference imageat a time different from the time of an encoding target current imagebased on a motion vector detected within a tile when a picture of thecurrent image is split into the tiles and encoded; an encoding unitencoding the current image and generating encoded data using theprediction image generated by the motion compensation unit; a settingunit setting tile splittable information indicating that decoding isallowed for each unit of the tiles; and a transmission unit transmittingthe encoded data generated by the encoding unit, and the tile splittableinformation set by the setting unit.

The encoding method according to the second aspect of the presenttechnique corresponds to the encoding device according to the secondaspect of the present technique.

According to the second aspect of the present technique, a predictionimage is generated by performing motion compensation of a referenceimage at a time different from the time of an encoding target currentimage based on a motion vector detected within a tile when a picture ofthe current image is split into the tiles and encoded. Encoded data isgenerated by encoding the current image using the prediction image. Tilesplittable information indicating that decoding is allowed for each unitof the tiles is set. The encoded data and the tile splittableinformation are transmitted.

Further, the decoding device of the first aspect and the encoding deviceof the second aspect can be realized by making a computer execute aprogram.

Moreover, the program executed by the computer for realizing thedecoding device of the first aspect and the encoding device of thesecond aspect can be provided by transmitting the program via atransmission medium, or by recording the program on a recording medium.

In addition, the decoding device of the first aspect and the encodingdevice of the second aspect may be separate devices, or may be insideblocks constituting one device.

Effects of the Invention

According to the first aspect of the present technique, independentdecoding in the time direction for each tile is allowed.

Moreover, according to the second aspect of the present technique,independent encoding in the time direction for each tile is allowed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram describing a reference image for conventional interprediction.

FIG. 2 is a block diagram showing a constitution example of aconventional decoding device.

FIG. 3 is a block diagram showing a constitution example of an encodingdevice to which the present technique is applied according to a firstembodiment.

FIG. 4 is a block diagram showing a constitution example of an encodingunit in FIG. 3.

FIG. 5 is a diagram describing tiles.

FIG. 6 is a diagram describing a restriction set when a motion vector isdetected.

FIG. 7 is a diagram describing a reference image for inter prediction.

FIG. 8 is a diagram showing an example of syntax of SPS.

FIG. 9 is a diagram showing an example of syntax of SPS.

FIG. 10 is a diagram showing an example of syntax of PPS.

FIG. 11 is a diagram showing an example of syntax of VUI.

FIG. 12 is a flowchart describing an encoded stream generating process.

FIG. 13 is a flowchart describing an encoding process in FIG. 12.

FIG. 14 is a flowchart describing the encoding process in FIG. 12.

FIG. 15 is a block diagram showing a constitution example of a decodingdevice to which the present technique is applied according to the firstembodiment.

FIG. 16 is a block diagram showing a constitution example of a decodingunit in FIG. 15 according to the first embodiment.

FIG. 17 is a diagram describing the outline of processing performed bythe decoding device in FIG. 15.

FIG. 18 is a flowchart describing an encoded stream decoding processperformed by the decoding device in FIG. 15.

FIG. 19 is a flowchart describing a decoding process in FIG. 16.

FIG. 20 is a diagram showing an example of an encoding target image ofan encoding device to which the present technique is applied accordingto a second embodiment.

FIG. 21 is a block diagram showing a constitution example of a decodingdevice for 2D image according to an embodiment.

FIG. 22 is a flowchart describing an encoded stream decoding processperformed by the decoding device in FIG. 21.

FIG. 23 is a block diagram showing a constitution example of atelevision conference system to which the present technique is appliedaccording to an embodiment.

FIG. 24 is a diagram showing another example of syntax of VUI.

FIG. 25 is a diagram showing an example of a multi-view image encodingsystem.

FIG. 26 is a diagram showing a constitution example of a multi-viewimage encoding device to which the present technique is applied.

FIG. 27 is a diagram showing a constitution example of the multi-viewimage encoding device to which the present technique is applied.

FIG. 28 is a diagram showing an example of a hierarchical image encodingsystem.

FIG. 29 is a diagram describing an example of spatial scalable encoding.

FIG. 30 is a diagram describing an example of temporal scalableencoding.

FIG. 31 is a diagram describing a signal to noise ratio scalableencoding.

FIG. 32 is a diagram showing a constitution example of a hierarchicalimage encoding device to which the present technique is applied.

FIG. 33 is a diagram showing a constitution example of the hierarchicalimage encoding device to which the present technique is applied.

FIG. 34 is a block diagram showing a constitution example of hardware ofa computer.

FIG. 35 is a diagram showing an example of the general structure of atelevision set to which the present technique is applied.

FIG. 36 is a diagram showing an example of the general structure of acellular phone to which the present technique is applied.

FIG. 37 is a diagram showing an example of the general structure of arecording and reproducing device to which the present technique isapplied.

FIG. 38 is a diagram showing an example of the general structure of animaging device to which the present technique is applied.

FIG. 39 is a block diagram showing an application example of scalableencoding.

FIG. 40 is a block diagram showing another application example ofscalable encoding.

FIG. 41 is a block diagram showing a further application example ofscalable encoding.

MODE FOR CARRYING OUT THE INVENTION First Embodiment ConstitutionExample of Encoding Device in First Embodiment

FIG. 3 is a block diagram showing a constitution example of an encodingdevice to which the present technique is applied according to a firstembodiment.

An encoding device 50 in FIG. 3 is constituted by an A/D conversion unit51, a screen rearrangement buffer 52, a split unit 53, encoding units54-1 through 54-N, a setting unit 55, and a transmission unit 56. Theencoding device 50 performs, for each tile, compression-encoding of animage in each unit of frames inputted as input signals by a systemcorresponding to HEVC system.

More specifically, the A/D conversion unit 51 of the encoding device 50performs A/D conversion of images in each unit of frames inputted asinput signals, and outputs the converted images to the screenrearrangement buffer 52 and allows the screen rearrangement buffer 52 tostore the images. The screen rearrangement buffer 52 rearranges thestored images in the respective units of frames located in the order ofdisplay in such positions that the images are located in the order ofencoding in accordance with Group of Picture (GOP) structure, andsupplies the rearranged images to the split unit 53.

The split unit 53 splits each of the images supplied by the screenrearrangement buffer 52 into N tiles based on information indicatingsplit positions of tiles and a split number N specified for each unit ofsequences in correspondence with operation of a not-shown input unitoperated by a user (hereinafter referred to as tile split information).The split unit 53 supplies the images of the N tiles to the encodingunits 54-1 through 54-N, respectively, as encoding target images.

The encoding units 54-1 through 54-N perform compression-encoding of theimages of the corresponding tiles supplied by the split unit 53independently in the time direction by a system corresponding to HEVCsystem. The encoding units 54-1 through 54-N supply encoded data of therespective tiles obtained as a result of the compression encoding to thesetting unit 55. Further, in the following description, the encodingunits 54-1 through 54-N are collectively referred to as the encodingunits 54 when distinction between the encoding units 54-1 through 54-Nis not particularly needed.

The setting unit 55 synthesizes the encoded data of the respective tilessupplied by the encoding units 54-1 through 54-N based on the tile splitinformation. In addition, the setting unit 55 sets Sequence ParameterSet (SPS), Picture Parameter Set (PPS), Video Usability Information(VUI), Adaption Parameter Set (APS), and the like based on the tilesplit information. The setting unit 55 generates an encoded stream byadding SPS, PPS, VUI, APS and the like to the synthesized encoded data,and supplies the generated encoded stream to the transmission unit 56.

The transmission unit 56 transmits the encoded stream supplied by thesetting unit 55 to a decoding device described later.

Constitution Example of Encoding Unit

FIG. 4 is a block diagram showing a constitution example of the encodingunit 54 in FIG. 3.

The encoding unit 54 in FIG. 4 is constituted by a calculation unit 71,an orthogonal transformation unit 72, a quantization unit 73, a losslessencoding unit 74, a store buffer 75, an inverse quantization unit 76, aninverse orthogonal transformation unit 77, an addition unit 78, adeblock filter 79, a DPB 80, a switch 81, an intra prediction unit 82,an inter prediction unit 83, a prediction image selection unit 84, and arate control unit 85.

An image of a corresponding tile is inputted from the split unit 53 inFIG. 3 to the encoding unit 54 as an encoding target image, and issupplied to the calculation unit 71, the intra prediction unit 82, andthe inter prediction unit 83.

The calculation unit 71 functions as an encoding unit, and calculatesthe difference between a prediction image supplied by the predictionimage selection unit 84 and the encoding target image to encode theencoding target image. More specifically, the calculation unit 71subtracts the prediction image from the encoding target image to encodethe encoding target image. The calculation unit 71 outputs the imageobtained as a result of the calculation to the orthogonal transformationunit 72 as residual information. When the prediction image is notsupplied by the prediction image selection unit 84, the calculation unit71 outputs the encoding target image to the orthogonal transformationunit 72 as it is as residual information.

The orthogonal transformation unit 72 performs orthogonal transformationof the residual information received from the calculation unit 71, andsupplies coefficients obtained as a result of the orthogonaltransformation to the quantization unit 73.

The quantization unit 73 quantizes the coefficients supplied by theorthogonal transformation unit 72. The quantized coefficients areinputted to the lossless encoding unit 74.

The lossless encoding unit 74 obtains information indicating the optimumintra prediction mode (hereinafter referred to as intra prediction modeinformation) from the intra prediction unit 82. Instead, the losslessencoding unit 74 obtains information indicating the optimum interprediction mode (hereinafter referred to as inter prediction modeinformation), a motion vector, information for specifying a referenceimage, and the like from the inter prediction unit 83.

The lossless encoding unit 74 performs lossless encoding of thequantized coefficients supplied by the quantization unit 73, such asvariable codeword length encoding (such as Context-Adaptive VariableLength Coding (CAVLC), and arithmetic encoding (such as CABAC).

In addition, the lossless encoding unit 74 performs differentialencoding of intra prediction mode information supplied by the intraprediction unit 82 using intra prediction mode information of aprediction block positioned adjacent to the prediction block of theintra prediction mode information and contained within the same tile.Instead, the lossless encoding unit 74 functions as a motion vectorgeneration unit which predicts a motion vector supplied by the interprediction unit 83 within the range of a predetermined restriction basedon Advanced Motion Vector Prediction (AMVP) or the like, and generatesthe difference between the corresponding prediction vector and theactual motion vector as motion vector information.

More specifically, according to AMVP or the like, motion vectors of aprediction block adjacent to the prediction block of the motion vectorinformation in the spatial direction, a co-located block (detailedbelow), a prediction block adjacent to the co-located block in thespatial direction, and the like are determined as prediction vectors.

Further, according to this specification, the condition “co-located”refers to a condition so disposed as to have the same positionalrelationship (positioned at the same place) in different pictures(frames, fields). Accordingly, the co-located block refers to a blockhaving the same positional relationship (positioned at the same place)in different pictures (frame, fields). Also, co-located pixels arepixels having the same positional relationship (positioned at the sameplace) in different pictures (frame, fields).

In addition, according to this specification, the adjacent (neighboring)condition refers to such a condition as to have a positionalrelationship allowing reference from a current picture (frame, field).It is preferable that this positional relationship corresponds to theposition immediately before or immediately after in view of time.However, this relationship is not required as long as the effects of thepresent technique can be offered. Further, the adjacent condition in thetime direction and the adjacent condition in the spatial direction arecollectively referred to as an adjacent condition when distinctiontherebetween is not particularly needed. The adjacent condition in thetime direction represents a positional relationship allowing referencein the time direction. The adjacent condition in the spatial directionrepresents to a positional relationship allowing reference within thesame picture.

The lossless encoding unit 74 restricts the prediction block of themotion vector defined as the prediction vector to the prediction blockswithin the same tile as the tile of the prediction block of the motionvector information. In this case, the decoding device is not required torefer to motion vectors of other tiles. Accordingly, the encoded dataafter inter prediction encoding can be decoded independently in the timedirection for each tile.

In addition, merging information may be used as the motion vectorinformation. The merging information is information indicating whether aprediction block of a motion vector is to be merged with anotherprediction block, and which prediction block the motion vector is to bemerged with at the time of merging. Possible prediction blocks formerging involve a prediction block adjacent to the prediction block ofthe motion vector in the spatial direction, a co-located block, and aprediction block adjacent to the co-located block in the spatialdirection, for example.

In this case, however, the possible prediction blocks for merging arerestricted to the prediction blocks within the same tile as the tile ofthe prediction block of the motion vector information. Accordingly, thedecoding device is not required to refer to motion vectors of othertiles; therefore, the encoded data after inter prediction encoding canbe independently decoded in the time direction for each tile.

The lossless encoding unit 74 determines whether the motion vectorsupplied by the inter prediction unit 83 is identical to any of themotion vectors of the possible prediction blocks for merging when themerging information is used as the motion vector information. Whendetermining as identical, the lossless encoding unit 74 generates, asmotion vector information, merging information indicating that mergingis performed with the possible prediction block for merging determinedas a vector identical block. On the other hand, when determining as notidentical, the lossless encoding unit 74 generates, as motion vectorinformation, merging information indicating that merging is notperformed.

The lossless encoding unit 74 performs lossless encoding of the intraprediction mode information after differential encoding, or the interprediction mode information, motion vector information, information forspecifying a reference image, and the like, and determines theinformation after lossless encoding as encoded information aboutencoding. The lossless encoding unit 74 supplies the coefficients andencoded information after lossless encoding to the store buffer 75 asencoded data and allows the store buffer 75 to store the encoded data.Further, the encoded information may be determined as header informationof the coefficients after lossless encoding.

The store buffer 75 temporarily stores the encoded data supplied by thelossless encoding unit 74. In addition, the store buffer 75 supplies thestored encoded data to the setting unit 55 in FIG. 3.

Furthermore, the quantized coefficients outputted from the quantizationunit 73 are also inputted to the inverse quantization unit 76, andinversely quantized and supplied to the inverse orthogonaltransformation unit 77.

The inverse orthogonal transformation unit 77 performs inverseorthogonal transformation of the coefficients supplied by the inversequantization unit 76, and supplies residual information obtained as aresult of the inverse orthogonal transformation to the addition unit 78.

The addition unit 78 adds the residual information as a decoding targetimage supplied by the inverse orthogonal transformation unit 77 to theprediction image supplied by the prediction image selection unit 84, andobtains a decoded image locally decoded for each unit of tiles. When theprediction image is not supplied by the prediction image selection unit84, the addition unit 78 determines the residual information supplied bythe inverse orthogonal transformation unit 77 as a decoded image locallydecoded for each unit of tiles. The addition unit 78 supplies thedecoded image locally decoded for each unit of tiles to the deblockfilter 79, and supplies the decoded image to the DPB 80 and allows theDPB 80 to store the decoded image.

The deblock filter 79 performs, for each unit of tiles, filtering of thedecoded image locally decoded for each unit of tiles supplied by theaddition unit 78. The filtering includes deblock filtering for removingblock distortion, sample adaptive offset (SAO) processing forsuppressing ringing, and adaptive loop filter (ALF) processing usingclass grouping or the like. The deblock filter 79 supplies the decodedimage for each unit of tiles obtained as a result of the filtering tothe DPB 80, and allows the DPB 80 to store the decoded image. Thedecoded image for each unit of tiles stored in the DPB 80 is outputtedvia the switch 81 to the intra prediction unit 82 or the interprediction unit 83 as a reference image.

The intra prediction unit 82 performs intra prediction of all possibleintra prediction modes by using a reference image read from the DPB 80via the switch 81 and not filtered by the deblock filter 79.

Moreover, the intra prediction unit 82 calculates cost function values(detailed later) for all the possible intra prediction modes based onthe encoding target image supplied by the split unit 53, and theprediction image generated as a result of the intra prediction. Then,the intra prediction unit 82 determines the intra prediction mode wherethe cost function value becomes the minimum as the optimum intraprediction mode, and supplies the prediction image generated in theoptimum intra prediction mode, and the corresponding cost function valueto the prediction image selection unit 84. When notified by theprediction image selection unit 84 about selection of the predictionimage generated in the optimum intra prediction mode, the intraprediction unit 82 supplies the intra prediction mode information to thelossless encoding unit 74.

It is noted herein that the cost function value is also called an RateDistortion (RD) cost, and calculated based on either High Complexitymode or Low Complexity mode defined in Joint Model (JM) as referencesoftware in H.264/AVC system, for example.

More specifically, when High Complexity mode is selected as acalculation method of the cost function value, steps up to losslessencoding are temporarily performed for all the possible predictionmodes. Then, the cost function value represented by the followingequation (1) is calculated for each prediction mode.[Equation 1]Cost(Mode)=D+λ·R  (1)

D is the difference (distortion) between the original image and thedecoded image. R is the generated amount of codes up to the coefficientsof orthogonal transformation. λ is a Lagrange multiplier given as afunction of a quantization parameter QP.

On the other hand, when Low Complexity mode is selected as thecalculation method for the cost function value, generation of thedecoded image, and calculation of the header bits of informationindicating the prediction modes and the like are performed for all thepossible prediction modes. Then, the cost function represented by thefollowing equation (2) is calculated for each prediction mode.[Equation 2]Cost(Mode)=D+QPtoQuant(QP)·Header_Bit  (2)

D is the difference (distortion) between the original image and thedecoded image. Header_Bit is header bits for a prediction mode.QPtoQuant is a function given as a function of a quantization parameterQP.

In Low Complexity mode, generation of decoded images for all theprediction modes is only needed, and the necessity of performinglossless encoding is eliminated. Accordingly, the amount of calculationdecreases.

The inter prediction unit 83 is constituted by a motion detection unit83A and a motion compensation unit 83B, and performs motion predictionand compensation processing of all the possible inter prediction modes.More specifically, the motion detection unit 83A performs motionprediction within the tile of the encoding target image by using theencoding target image supplied by the split unit 53, and a referenceimage read from the DPB 80 via the switch 81, positioned at a timedifferent from the time of the corresponding encoding target image, andfiltered by the deblock filter 79.

More specifically, the motion detection unit 83A detects motion vectorsfor all the possible inter prediction modes by using the encoding targetimage, and a reference image filtered, contained within the same tile asthe tile of the encoding target image, and positioned in a framedifferent from the frame of the encoding target image. The motioncompensation unit 83B performs inter prediction by performing motioncompensation of the reference image filtered by the deblock filter 79based on the motion vectors detected by the motion detection unit 83A,and generates a prediction image.

At this time, the inter prediction unit 83 calculates the cost functionvalues for all the possible inter prediction modes based on the encodingtarget image and the prediction image, and determines the interprediction mode where the cost function value becomes the minimum as theoptimum inter measurement mode. Then, the inter prediction unit 83supplies the cost function value for the optimum inter prediction mode,and the corresponding prediction image to the prediction image selectionunit 84. In addition, the inter prediction unit 83 outputs the interprediction mode information, the corresponding motion vector, theinformation for specifying a reference image, and the like to thelossless encoding unit 74 when notified from the prediction imageselection unit 84 about selection of the prediction image generated inthe optimum inter prediction mode.

The prediction image selection unit 84 selects the prediction mode wherethe corresponding cost function value is smaller from the optimum intraprediction mode and the optimum inter prediction mode based on the costfunction values supplied by the intra prediction unit 82 and the interprediction unit 83, and determines the selected prediction mode as theoptimum prediction mode. Then, the prediction image selection unit 84supplies the prediction image in the optimum prediction mode to thecalculation unit 71 and the addition unit 78. Moreover, the predictionimage selection unit 84 notifies the intra prediction unit 82 or theinter prediction unit 83 about selection of the prediction image in theoptimum prediction mode.

The rate control unit 85 controls the rate of the quantizing operationof the quantization unit 73 based on the encoded data stored in thestore buffer 75 such that neither overflow nor underfloor occurs.

Description of Tile

FIG. 5 is a diagram showing tiles.

As shown in FIG. 5, one picture (frame) can be split into a plurality oftiles and encoded. According to the example in FIG. 5, one picture issplit into four tiles. Each tile is given a tile ID starting from 0 inthe order of raster scan. Further, Largest Coding Units (LCUs) within atile are encoded in the order of raster scan.

Moreover, one picture can also be split into a plurality of slices. Theboundaries between the respective tiles may be either identical to ordifferent from the boundaries between the respective slices. Accordingto the example in FIG. 5, each of a tile #0 having a tile ID of 0 and atile #1 having a tile ID of 1 is constituted by two slices. Also, eachof a tile #3 having a tile ID of 3 and a tile #4 having a tile ID of 4constitutes one slice. According to this embodiment, however, aplurality of tiles does not constitute one slice. In other words, a tilecontains at least one slice. Accordingly, encoded data of each tilealways contains a slice header; therefore, encoding can be performed foreach unit of tiles. Furthermore, when one tile contains a plurality ofslices, the slices within the corresponding tile are encoded in theorder of raster scan.

Description of Restriction on Motion Vector Detection

FIG. 6 is a diagram showing a restriction set when the motion detectionunit 83A in FIG. 4 detects motion vectors.

As shown in FIG. 6, the motion detection unit 83A performs motionprediction within a tile by setting such a restriction that possiblereference images of a CU within a tile #i having a tile ID of i are onlyimages within the tile #i. Accordingly, a motion vector MV (mvx, mvy)(unit: pixel) satisfies the following equation (3).[Equation 3]x+mvx≥minX_in_TileID_iy+mvy≥minY_in_TileID_ix+w+mvx<maxX_in_TileID_iy+h+mvy<maxY_in_TileID_i  (3)

Further, in the equation (3), (x, y) are coordinates of a pixel unitcorresponding to a pixel located at the upper left of the CU, and eachof w and h is a length of a pixel unit in the horizontal width and thevertical width, respectively. Moreover, minX_in_TileID_i corresponds tothe x coordinate value of the pixel at the upper left of the tile #i,and minY_in_TileID_i corresponds to the y coordinate value of the pixelat the upper left of the tile #i. Furthermore, maxX_in_TileID_icorresponds to the x coordinate value of the pixel at the lower right ofthe tile #i, and maxY_in_TileID_i corresponds to the y coordinate valueof the pixel at the lower right of the tile #i.

The restriction established at the time of detection of the motionvector as discussed above eliminates the necessity of using a decodedimage of another tile, as shown in FIG. 7, as a reference image in thetime direction at the time of inter prediction.

More specifically, as shown in FIG. 7, inter prediction of the CU withinthe tile #1 of the frame #t is performed by using an image within thetile #1 of the frame #t−1 as a reference image when each of the frame #thaving a POC of t and the frame #t−1 having a POC of t−1 is split intofour tiles. Similarly to the tile #1, inter prediction is performed forthe respective CUs of tiles #2 through #4 by using images within theirown tile #2, tile #3, and tile #4 as reference images. Accordingly,independent inter prediction in the time direction for each tile isallowed.

Example of SPS

FIGS. 8 and 9 show an example of syntax of SPS set by the setting unit55 in FIG. 3.

As shown in lines 19 through 28 in FIG. 9, tile split information foreach unit of sequences is set for SPS. The tile split informationincludes num_tile_columns_minus1 shown in line 20, num_tile_rows_minus1shown in line 21, column_width[i] shown in line 25, row_height[i] shownin line 27, and the like.

Num_tile_columns_minus1 represents the number of tiles in the columndirection (horizontal direction), while num_tile_rows_minus1 representsthe number of tiles in the row direction (vertical direction). Also,column_width[i] represents the length of a pixel unit in the horizontaldirection of each tile, while row_height[i] represents the length of apixel unit in the vertical direction of each tile.

Moreover, as shown in line 29 in FIG. 9, deblock filter information(filter information) (loop_filter_across_tiles_enabled_flag)representing whether filtering is performed across plural tiles in areference image is set for each unit of sequences in SPS. The deblockfilter 79 of the encoding device 50 performs filtering for each unit oftiles; therefore, the setting unit 55 sets the deblock filterinformation to false (0).

Example of PPS

FIG. 10 shows an example of syntax of PPS set by the setting unit 55 inFIG. 3.

As shown in line 21 in FIG. 10, tile_info_present_flag representingwhether tile split information is controlled for each unit of picturesis set for PPS. The setting unit 55 sets tile_info_present_flag to false(0). In this case, the fixed tile diving method is maintained within asequence for the encoding device 50, and is not changed betweenpictures.

In addition, when the tile split information for each unit of picturesas described later is identical between images within the same sequence,tile_info_present_flag may be set to true (1).

Moreover, as shown in lines 23 through 33, tile split information foreach unit of pictures is set for PPS similarly to the tile splitinformation for each unit of sequences in FIG. 9. Furthermore, as shownin line 35, deblock filter information for each unit of pictures is setfor PPS.

Example of VUI

FIG. 11 show an example of syntax of VUI set by the setting unit 55 inFIG. 3.

As shown in line 4 in FIG. 11, tile splittable information(tile_splittable_flag) is set for VUI. The tile splittable informationis information indicating whether decoding is allowed for each unit oftiles. The encoding device 50 allows decoding for each unit of tiles byperforming motion prediction within a tile and setting variousrestrictions. Thus, the setting unit 55 sets the tile splittableinformation to true (1).

When bitstream_restriction_flag in line 1 is 0, the decoding siderecognizes that decoding is not allowed for each tile based on theconsideration that the tile splittable information is false (0).

Description of Process Performed by Encoding Device

FIG. 12 is a flowchart describing an encoded stream generating processperformed by the encoding device 50 in FIG. 3.

In step S11 in FIG. 12, the A/D conversion unit 51 performs A/Dconversion of an image of each unit of frames inputted as input signals,and outputs the converted image to the screen rearrangement buffer 52and allows the screen rearrangement buffer 52 to store the image.

In step S12, the screen rearrangement buffer 52 rearranges the storedimages of the respective frames located in the display order in suchpositions that the images are located in the order of encoding inaccordance with the GOP structure, and supplies the rearranged images tothe split unit 53.

In step S13, the split unit 53 splits each of the images supplied by thescreen rearrangement buffer 52 into N tiles based on the tile splitinformation. The split unit 53 supplies each of the images containingthe N tiles to the corresponding encoding units 54-1 through 54-N as animage of an encoding unit.

In step S14, the encoding units 54 perform an encoding process whichcompression-encodes the images of the corresponding tiles supplied bythe split unit 53 independently in the time direction by a systemcorresponding to HEVC system. The details of the encoding process willbe described with reference to FIGS. 13 and 14 discussed below.

In step S15, the setting unit 55 synthesizes encoded data of therespective tiles supplied by the encoding units 54-1 through 54-N basedon the tile split information.

In step S16, the setting unit 55 sets the tile splittable information ofVUI to 1. In step S17, the setting unit 55 sets the deblock filterinformation of SPS and PPS to 0. In addition, the setting unit 55 setsinformation on SPS, PPS, VUI, APS and the like other than the tilesplittable information based on the tile split information and the like.

At this time, the setting unit 55 sets sao_repeat_row_flag andsao_merge_up_flag contained in APS and indicating whether SAO processingis performed using parameters of SAO processing of the adjacent image tofalse (0) when the adjacent image is an image of a different tile.Moreover, the setting unit 55 sets alf_repeat_row_flag andalf_merge_up_flag contained in APS and indicating whether ALF processingis performed using parameters of ALF processing of the adjacent image tofalse (0) when the adjacent image is an image of a different tile. Inthis case, parameters for SAO processing and parameters for ALFprocessing are not shared between different tiles. Accordingly,filtering is performed for each unit of tiles for encoding.

As discussed above, sao_repeat_row_flag, sao_merge_up_flag,alf_repeat_row_flag and alf_merge_up_flag are set to false (0) when theadjacent image is an image of a different tile. Accordingly, these setsof information are considered as parameter sharing informationrepresenting that parameters in filtering are not shared between tiles.

In step S18, the setting unit 55 generates an encoded stream by addingSPS, PPS, VUI, APS and the like to the synthesized encoded data, andsupplies the encoded stream to the transmission unit 56.

In step S19, the transmission unit 56 transmits the encoded streamsupplied by the setting unit 55 to the decoding device described later,and terminates the process.

Description of Process Performed by Encoding Device

FIGS. 13 and 14 are a flowchart describing step S14 of the encodingprocess in FIG. 12. This encoding process is performed for each unit ofCUs, for example.

In step S30, the intra prediction unit 82 performs an intra predictionprocess for performing intra prediction for all possible intraprediction modes by using an image stored in the DPB 80, located in thesame tile as the tile of the encoding target image, and not filtered asa reference image. At this time, the intra prediction unit 82 calculatescost function values for all the possible intra prediction modes basedon the encoding target image supplied by the split unit 53 and aprediction image generated as a result of the intra prediction. Then,the intra prediction unit 82 determines the intra prediction mode wherethe cost function value becomes the minimum as the optimum intraprediction mode, and supplies a prediction image generated in theoptimum intra prediction mode and the corresponding cost function valueto the prediction image selection unit 84.

In addition, the inter prediction unit 83 performs motion prediction andmotion compensation within a tile for all the possible inter predictionmodes by using a filtered image stored in the DPB 80, and located in thesame tile as the tile of the encoding target image as a reference image.At this time, the inter prediction unit 83 calculates cost functionvalues for all the possible inter prediction modes based on the encodingtarget image supplied by the split unit 53, and a prediction imagegenerated as a result of the motion compensation. Then, the interprediction unit 83 determines the inter prediction mode where the costfunction values becomes the minimum as the optimum inter predictionmode, and supplies a prediction image generated in the optimum interprediction mode and the corresponding cost function value to theprediction image selection unit 84.

In step S31, the prediction image selection unit 84 selects theprediction mode where the cost function value becomes the minimum fromthe optimum intra prediction mode and the optimum inter prediction modebased on the cost function values supplied by the intra prediction unit82 and the inter prediction unit 83 by the processing in step S30, anddetermines the selected prediction mode as the optimum prediction mode.Then, the prediction image selection unit 84 supplies a prediction imagein the optimum prediction mode to the calculation unit 71 and theaddition unit 78.

In step S32, the prediction image selection unit 84 determines whetherthe optimum prediction mode is the optimum inter prediction mode or not.When it is determined that the optimum prediction mode is the optimuminter prediction mode in step S32, the prediction image selection unit84 notifies the inter prediction unit 83 about selection of theprediction image generated in the optimum inter prediction mode. As aresult, the inter prediction unit 83 outputs the inter prediction modeinformation, the corresponding motion vector, and the information forspecifying a reference image to the lossless encoding unit 74.

Then, in step S33, the lossless encoding unit 74 predicts the motionvector supplied by the inter prediction unit 83 based on AMVP or thelike, and generates the difference between the prediction vector and theactual motion vector as motion vector information. At this time, theprediction block of the motion vector determined as the predictionvector in AMVP is restricted to any of the prediction blocks within thesame tile as the tile of the prediction block of the motion vectorinformation.

In step S34, the lossless encoding unit 74 performs lossless encoding ofthe inter prediction mode information, the information for specifying areference image, and the motion vector information supplied by the interprediction unit 83, and determines the information thus obtained asencoded information. Then, the process proceeds to step S36.

On the other hand, when it is determined that the optimum predictionmode is not the optimum inter prediction mode in step S32, in otherwords, when the optimum prediction mode is the optimum intra predictionmode, the prediction image selection unit 84 notifies the intraprediction unit 82 about selection of the prediction image generated inthe optimum intra prediction mode. As a result, the intra predictionunit 82 supplies the intra prediction mode information to the losslessencoding unit 74.

Then, in step S35, the lossless encoding unit 74 performs differentialencoding of the intra prediction mode information supplied by the intraprediction unit 82, and further performs lossless encoding of theresultant information to provide the information thus obtained asencoded information. Then, the process proceeds to step S36.

In step S36, the calculation unit 71 subtracts the prediction imagesupplied by the prediction image selection unit 84 from the encodingtarget image supplied by the split unit 53. The calculation unit 71outputs the image obtained as a result of the subtraction to theorthogonal transformation unit 72 as residual information.

In step S37, the orthogonal transformation unit 72 performs orthogonaltransformation of the residual information received from the calculationunit 71, and supplies coefficients obtained as a result of theorthogonal transformation to the quantization unit 73.

In step S38, the quantization unit 73 quantizes the coefficientssupplied by the orthogonal transformation unit 72. The quantizedcoefficients are inputted to the lossless encoding unit 74 and theinverse quantization unit 76.

In step S39, the lossless encoding unit 74 performs lossless encoding ofthe coefficients quantized and supplied by the quantization unit 73. Thelossless encoding unit 74 generates encoded data from informationobtained as a result of the lossless encoding and the encodedinformation generated by the processing in step S34 or S35.

In step S40 in FIG. 14, the lossless encoding unit 74 supplies theencoded data to the store buffer 75, and allows the store buffer 75 tostore the data.

In step S41, the store buffer 75 outputs the stored encoded data to thesetting unit 55 (FIG. 3).

In step S42, the inverse quantization unit 76 performs inversequantization of the quantized coefficients supplied by the quantizationunit 73.

In step S43, the inverse orthogonal transformation unit 77 performsinverse orthogonal transformation of the coefficients supplied by theinverse quantization unit 76, and supplies the residual informationobtained as a result of the inverse orthogonal transformation to theaddition unit 78.

In step S44, the addition unit 78 adds the residual information suppliedby the inverse orthogonal transformation unit 77 to the prediction imagesupplied by the prediction image selection unit 84 to obtain a decodedimage locally decoded for each unit of tiles. The addition unit 78supplies the obtained decoded image for each unit of tiles to thedeblock filter 79, and supplies the decoded image to the DPB 80.

In step S45, the deblock filter 79 performs, for each unit of tiles,filtering of the decoded image locally decoded for each unit of tilesand supplied by the addition unit 78. The deblock filter 79 supplies thedecoded image obtained as a result of the filtering for each unit oftiles to the DPB 80.

In step S46, the DPB 80 stores the decoded images for each unit of tilesbefore and after the filtering. More specifically, the DPB 80 stores thedecoded images for each unit of tiles supplied by the addition unit 78and the decoded images for each unit of tiles supplied by the deblockfilter 79. The decoded images for each unit of tiles stored in the DPB80 are outputted via the switch 81 to the intra prediction unit 82 orthe inter prediction unit 83 as reference images. Then, the processreturns to step S14 in FIG. 12, and proceeds to step S15.

Further, according to the encoding process in FIG. 13 and FIG. 14, boththe intra prediction, and motion prediction and motion compensation arealways performed for simplification of the description. However, inpractical cases, only either of these processes may be performeddepending on picture types or other conditions.

As discussed herein, the encoding device 50 performs motion predictionwithin a tile, and generates a motion vector by using an encoding targetimage and a reference image at a time different from the time of theencoding target image. Accordingly, independent encoding in the timedirection for each tile is allowed.

Further, while the encoding device 50 is provided with the N encodingunits 54 for encoding images of respective tiles, the encoding device 50may be provided with only one encoding unit. In this case, the encodingunit has a DPB storing a decoded image for each tile, and encodes imagesper tile in the order of the tile ID number in the direction fromsmaller number to larger number, that is, the order of raster scan.

Constitution Example of Decoding Device in First Embodiment

FIG. 15 is a bock diagram showing a constitution example of a decodingdevice to which the present technique is applied according to the firstembodiment. This decoding device decodes an encoded stream transmittedfrom the encoding device 50 in FIG. 3.

A decoding device 90 in FIG. 15 is constituted by a reception unit 91,an extraction unit 92, a split unit 93, decoding units 94-1 through94-N, a screen rearrangement buffer 95, and a D/A conversion unit 96.

The reception unit 91 of the decoding device 90 receives an encodedstream transmitted from the encoding device 50, and supplies the encodedstream to the extraction unit 92.

The extraction unit 92 extracts SPS, PPS, VUI, APS, encoded data and thelike from the encoded stream, and supplies the extraction to the splitunit 93. In addition, the extraction unit 92 supplies tile splitinformation contained in SPS and PPS to the screen rearrangement buffer95.

The split unit 93 splits the encoded data into units of tiles based ontile splittable information contained in VUI supplied by the extractionunit 92, and the tile split information contained in SPS and PPS. Thesplit unit 93 supplies the encoded data of N tiles obtained as a resultof the split to the decoding units 94-1 through 94-N for each tile, Inaddition, the split unit 93 supplies SPS, PPS, APS and the like suppliedby the extraction unit 92 to the decoding unit 94-N.

Each of the decoding units 94-1 through 94-N decodes encoded data of thecorresponding tile supplied by the split unit 93 by a systemcorresponding to HEVC system while referring to SPS, PPS, APS and thelike supplied by the split unit 93. In other words, the decoding units94-1 through 94-N decode the encoded data independently in the timedirection for each tile while referring to SPS, PPS, APS and the like.The decoding units 94-1 through 94-N supply the decoded images obtainedas a result of the decoding to the screen rearrangement buffer 95. Inthe following description, the decoding units 94-1 through 94-N arecollectively referred to as decoding units 94 when distinctiontherebetween is not particularly required.

The screen rearrangement buffer 95 synthesizes the decoded images of therespective tiles supplied by the decoding units 94-1 through 94-N byarranging the respective decoded images and storing the respectivedecoded images for each unit of frames based on the tile splitinformation supplied by the extraction unit 92. The screen rearrangementbuffer 95 rearranges the stored images for each unit of frames locatedin the order of encoding in such positions that the respective imagesare located in the order of the original display, and supplies therearranged images to the D/A conversion unit 96.

The D/A conversion unit 96 performs D/A conversion of the images foreach unit of frames supplied by the screen rearrangement buffer 95, andsupplies the converted image as output signals.

Constitution Example of Decoding Unit

FIG. 16 is a block diagram showing a constitution example of thedecoding units 94 in FIG. 15 according to the first embodiment.

The decoding unit 94 in FIG. 16 is constituted by a store buffer 101, alossless decoding unit 102, an inverse quantization unit 103, an inverseorthogonal transformation unit 104, an addition unit 105, a deblockfilter 106, a DPB 107, a switch 108, an intra prediction unit 109, amotion compensation unit 110, and a switch 111.

The store buffer 101 of the decoding unit 94 receives encoded data ofthe corresponding tile supplied by the split unit 93 in FIG. 15, andstores the received data. The store buffer 101 supplies the storedencoded data to the lossless decoding unit 102.

The lossless decoding unit 102 performs lossless decoding, such asvariable codeword length decoding and arithmetic decoding, for theencoded data received from the store buffer 101 to obtain quantizedcoefficients and encoded information. The lossless decoding unit 102supplies the quantized coefficients to the inverse quantization unit103.

In addition, the lossless decoding unit 102 obtains intra predictionmode information of the current prediction block by adding intraprediction mode information after differential encoding as encodedinformation to intra prediction mode information of a prediction blockadjacent to the current prediction block within the same tile. Thelossless decoding unit 102 supplies the current intra prediction modeinformation and the like to the intra prediction unit 109.

Moreover, the lossless decoding unit 102 functions as a motion vectorgeneration unit, and calculates a motion vector of the currentprediction block by adding motion vector information as encodedinformation to a motion vector of another prediction block within thesame tile. The lossless decoding unit 102 supplies the obtained motionvector, information for specifying a reference image as encodedinformation, inter prediction mode information and the like to themotion compensation unit 110. Furthermore, the lossless decoding unit102 supplies intra prediction mode information or inter prediction modeinformation to the switch 111.

The inverse quantization unit 103, the inverse orthogonal transformationunit 104, the addition unit 105, the deblock filter 106, the DPB 107,the switch 108, the intra prediction unit 109, and the motioncompensation unit 110 perform operations similar to the correspondingoperations of the inverse quantization unit 76, the inverse orthogonaltransformation unit 77, the addition unit 78, the deblock filter 79, theDPB 80, the switch 81, the intra prediction unit 82, and the motioncompensation unit 83 in FIG. 4. The images are decoded by theseoperations.

More specifically, the inverse quantization unit 103 performs inversequantization of the quantized coefficients supplied by the losslessdecoding unit 102, and supplies the coefficients obtained as a result ofthe inverse quantization to the inverse orthogonal transformation unit104.

The inverse orthogonal transformation unit 104 performs inverseorthogonal transformation of the coefficients received from the inversequantization unit 103, and supplies residual information obtained as aresult of the inverse orthogonal transformation to the addition unit105.

The addition unit 105 functions as a decoding unit, and adds residualinformation as the decoding target image supplied by the inverseorthogonal transformation unit 104 to the prediction image supplied bythe switch 111 for decoding. The addition unit 105 supplies a decodedimage obtained as a result of the decoding to the deblock filter 106,and supplies the decoded image to the DPB 107. When the prediction imageis not supplied by the switch 111, the addition unit 105 supplies theimage corresponding to the residual information supplied by the inverseorthogonal transformation unit 104 to the deblock filter 106 as adecoded image, and supplies the image to the DPB 107 and allows the DPB107 to store the image.

The deblock filter 106 removes block distortion by performing filteringof the decoded image supplied by the addition unit 105 for each unit oftiles based on deblock filter information contained in SPS and PPSsupplied by the split unit 93. The deblock filter 106 supplies a decodedimage obtained as a result of the filtering to the DPB 107 and allowsthe DPB 107 to store the image, and supplies the image to the screenrearrangement buffer 95 in FIG. 15. The decoded image of thecorresponding tile stored in the DPB 107 is read via the switch 108 as areference image, and supplied to the motion compensation unit 110 or theintra prediction unit 109.

The intra prediction unit 109 performs intra prediction in the optimumintra prediction mode indicated by the intra prediction mode informationby using a reference image read from the DPB 107 via the switch 108, notfiltered by the deblock filter 106, and contained in the same tile asthe tile of the decoding target image. The intra prediction unit 109supplies a prediction image generated as a result of the intraprediction to the switch 111.

The motion compensation unit 110 reads, from the DPB 107 via the switch108, a reference image contained in a frame different from the frame ofthe decoding target image, contained in the same tile as the tile of thedecoding target image, and filtered by the deblock filter 106 based oninformation for specifying a reference image supplied by the losslessdecoding unit 102. In other words, the motion compensation unit 110reads a reference image contained in a co-located tile from the DPB 107based on the information for specifying a reference image.

The motion compensation unit 110 performs inter prediction in theoptimum inter prediction mode by performing motion compensation of thereference image in the optimum inter prediction mode indicated by theinter prediction mode information based on the motion vector. The motioncompensation unit 110 supplies a prediction image generated as a resultof the inter prediction to the switch 111.

The switch 111 supplies the prediction image supplied by the intraprediction unit 109 to the addition unit 105 when the intra predictionmode information is supplied by the lossless decoding unit 102. On theother hand, when the inter prediction mode information is supplied bythe lossless decoding unit 102, the switch 111 supplies the predictionimage supplied by the motion compensation unit 110 to the addition unit105.

Description of Outline of Process Performed by Decoding Device

FIG. 17 is a diagram describing the outline of a process performed bythe decoding device 90 in FIG. 15.

As shown in FIG. 17, an encoded stream divided into N tiles and encodedis inputted to the decoding device 90 from the encoding device 50.Further, the tile splittable information is set to true (1) for thisencoded stream.

The decoding device 90 receives the encoded stream, extracts SPS, PPS,VUI, APS, encoded data and the like from the encoded stream, and splitsthe encoded data into units of tiles based on tile split informationcontained in SPS and PPS. The encoded data for each tile obtained bysplit is supplied to the corresponding decoding units 94-1 through 94-Nfor each tile. More specifically, each of the encoded data of tile #1,tile #2, and up to tile #N is supplied to the corresponding decodingunit 94-1, decoding unit 94-2, and up to decoding unit 94-N.

The decoding unit 94-1 is constituted by a decoding processing unit121-1 and a DPB 122-1. The decoding processing unit 121-1 is constitutedby the store buffer 101, the lossless decoding unit 102, the inversequantization unit 103, the inverse orthogonal transformation unit 104,the addition unit 105, the deblock filter 106, the DPB 107, the switch108, the intra prediction unit 109, the motion compensation unit 110,and the switch 111 (FIG. 16) of the decoding unit 94-1. The decodingprocessing unit 121-1 decodes the encoded data of the tile #1.

Moreover, the DPB 122-1 is constituted by the DPB 107 of the decodingunit 94-1, and stores the decoded image of the tile #1 obtained as aresult of the decoding by the decoding processing unit 121-1. Thedecoded image of the tile #1 stored in the DPB 122-1 is used fordecoding by the decoding processing unit 121-1.

Each of the decoding units 94-2 through 94-N has a constitution similarto the structure of the decoding unit 94-1. Accordingly, the decodedimages of the tile #2 through tile #N are stored in the DPB 122-2through 122-N, respectively.

In addition, the decoded images of the tile #1 through tile #N obtainedby the decoding processing unit 121-1 through 121-N are also supplied tothe screen rearrangement buffer 95, synthesized by arrangement based onthe tile split information, and stored for each unit of frames.

As discussed above, the encoded data for each tile is decodedindependently by using the decoding image of the corresponding tile.Accordingly, the decoding device 90 is not required to include a commondecoding DPB retaining decoded images for all tiles.

Description of Process Performed by Decoding Device

FIG. 18 is a flowchart describing an encoded stream decoding processperformed by the decoding device 90 in FIG. 15.

In step S61 in FIG. 18, the reception unit 91 of the decoding device 90receives an encoded stream transmitted from the encoding device 50, andsupplies the encoded stream to the extraction unit 92.

In step S62, the extraction unit 92 extracts SPS, PPS, VUI, APS, encodeddata and the like from the encoded stream, and supplies the extractionto the split unit 93. In addition, the extraction unit 92 supplies tilesplit information contained in SPS and PPS to the screen rearrangementbuffer 95.

In step S63, the split unit 93 determines whether tile splittableinformation contained in VUI supplied by the extraction unit 92 is true(1) or not. When the tile splittable information is not true (1), thatis, when the tile splittable information is false (0), the split unit 93terminates the process.

On the other hand, when it is determined that the tile splittableinformation is true (1) in step S63, the split unit 93 splits theencoded data into units of tiles based on the tile split informationcontained in the split unit 93, SPS and PPS in step S64.

In step S65, the split unit 93 supplies the encoded data of therespective split N tiles to the corresponding decoding units 94-1through 94-N. Moreover, the split unit 93 supplies SPS, PPS and the likesupplied by the extraction unit 92 to the decoding unit 94-N.

In step S66, the decoding units 94 perform decoding of the encoded dataof the corresponding tiles supplied by the split unit 93 by a systemcorresponding to HEVC system while referring to SPS, PPS and the likesupplied by the split unit 93. The details of this decoding process willbe described with reference to FIG. 19 discussed later.

In step S67, the screen rearrangement buffer 95 synthesizes the decodedimages of the respective tiles supplied by the decoding units 94-1through 94-N by arranging the respective decoding images and storing therespective decoding images for each unit of frames based on the tilesplit information supplied by the extraction unit 92.

In step S68, the screen rearrangement buffer 95 rearranges the storedimages for each unit of frames located in the order for encoding in suchpositions that the respective images are located in the order of theoriginal display, and supplies the rearranged images to the D/Aconversion unit 96.

In step S69, the D/A conversion unit 96 performs D/A conversion of theimages for each unit of frames supplied by the screen rearrangementbuffer 95, and outputs the converted images as output signals.

FIG. 19 is a flowchart describing the decoding process performed in stepS66 in FIG. 18.

In step S100 in FIG. 19, the store buffer 101 of the decoding unit 94receives encoded data of the corresponding tile from the split unit 93in FIG. 15, and stores the data. The store buffer 101 supplies theencoded data stored therein to the lossless decoding unit 102. Further,the following processes from S101 to S110 are performed for each unit ofCUs, for example.

In step S101, the lossless decoding unit 102 performs lossless decodingof the encoded data received from the store buffer 101, and obtainsquantized coefficients and encoded information. The lossless decodingunit 102 supplies the quantized coefficients to the inverse quantizationunit 103.

In addition, the lossless decoding unit 102 obtains intra predictionmode information of the current prediction block by adding intraprediction mode information after differential encoding as encodedinformation to intra prediction mode information of a prediction blockadjacent to the current block within the same tile. The losslessdecoding unit 102 supplies intra prediction mode information of thecurrent prediction block to the intra prediction unit 109 and the switch111.

In step S102, the lossless decoding unit 102 generates a motion vectorof the current prediction block by adding motion vector information asencoded information to a motion vector of another prediction blockwithin the same tile. The lossless decoding unit 102 supplies thegenerated motion vector, information for specifying a reference image asencoded information, inter prediction mode information and the like tothe motion compensation unit 110. In addition, the lossless decodingunit 102 supplies the inter prediction mode information to the switch111.

In step S103, the inverse quantization unit 103 performs inversequantization of the quantized coefficients received from the losslessdecoding unit 102, and supplies the coefficients obtained as a result ofthe inverse quantization to the inverse orthogonal transformation unit104.

In step S104, the motion compensation unit 110 determines whether theinter prediction mode information is supplied from the lossless decodingunit 102. When it is determined that the inter prediction modeinformation is supplied in step S104, the process proceeds to step S105.

In step S105, the motion compensation unit 110 performs motioncompensation by using a reference image filtered by the deblock filter106 and contained in the same tile as the tile of the decoding targetimage based on the motion vector, the inter prediction mode information,and the information for specifying a reference image supplied by thelossless decoding unit 102. The motion compensation unit 110 supplies aprediction image generated as a result of the motion compensation to theaddition unit 105 via the switch 111, and allows the process to proceedto step S107.

On the other hand, when it is determined that the inter prediction modeinformation is not supplied in step S104, that is, when the intraprediction mode information is supplied to the intra prediction unit109, the process proceeds to step S106.

In step S106, the intra prediction unit 109 performs intra predictionprocess which performs intra prediction of the intra prediction modeinformation by using a reference image read from the DPB 107 via theswitch 108, not filtered by the deblock filter 106, and located withinthe same tile as the tile of the decoding target image. The intraprediction unit 109 supplies a prediction image generated as a result ofthe intra prediction to the addition unit 105 via the switch 111, andallows the process to proceed to step S107.

In step S107, the inverse orthogonal transformation unit 104 performsinverse orthogonal transformation of the coefficients received from theinverse quantization unit 103, and supplies residual informationobtained as a result of the inverse orthogonal transformation to theaddition unit 105.

In step S108, the addition unit 105 performs decoding by adding theresidual information supplied by the inverse orthogonal transformationunit 104 as a decoding target image to the prediction image supplied bythe switch 111. The addition unit 105 supplies a decoded image obtainedas a result of the decoding to the deblock filter 106, and also suppliesthe decoded image to the DPB 107.

In step S109, the deblock filter 106 performs filtering of the decodedimage supplied by the addition unit 105 for each unit of tiles based ondeblock filter information contained in SPS and PPS supplied by thesplit unit 93. The deblock filter 106 supplies a decoded image afterfiltering to the DPB 107 and the screen rearrangement buffer 95 (FIG.15).

In step S110, the DPB 107 stores the decoded image before filteringsupplied by the addition unit 105, and the decoded image after filteringsupplied by the deblock filter 106. The decoded image stored in the DPB107 is supplied to the motion compensation unit 110 or to the intraprediction unit 109 via the switch 108. Then, the process returns tostep S66 in FIG. 18, and proceeds to step S67.

As discussed above, the decoding device 90 performs motion compensationfor each tile by using a reference image positioned at a time differentfrom the time of the decoding target image and contained within the sametile as the tile of the decoding target image based on the tilesplittable information and the motion vector information. Accordingly,independent decoding in the time direction for each tile is allowed. Asa result, the decoding device 90 can reproduce only a predetermined tileof the N tiles at a high speed, for example.

Further, while the decoding device 90 is provided with the N decodingunits 94 for decoding images of the respective tiles, the decodingdevice 90 may be provided with the one decoding unit 94. In this case,the decoding unit includes a DPB storing decoded images for each tile,and performs decoding of images for each tile in the order of tile IDnumber in the direction from smaller number to larger number, that is,in the order of raster scan.

Second Embodiment Example of Encoding Target Image

FIG. 20 is a diagram showing an example of an encoding target image ofan encoding device to which the present technique is applied accordingto a second embodiment.

As shown in FIG. 20, the encoding target image is an image formed as a3D image for 3D display, containing a left-eye image (hereinafterreferred to as L image) disposed on the left half of the screen, and aright-eye image (hereinafter referred to as R image) disposed on theright half of the screen.

In addition, as shown in FIG. 20, the encoding target image istile-split into different tiles for the L image and for the R image. Asa result, the tile for L image becomes a tile #0, and the tile for the Rimage becomes a tile #1.

Further, the L image and the R image of the 3D image may be disposed onthe upper half and the lower half of the screen, respectively.

Constitution Example of Encoding Device in Second Embodiment

The encoding device to which the present technique is applied accordingto the second embodiment is the encoding device 50 which sets N to 2.This encoding device independently encodes the L image and the R image,and transmits an encoded stream obtained as a result of the encoding.

Constitution Example of Decoding Device for 2D Image in an Embodiment

FIG. 21 is a block diagram showing a constitution example of a decodingdevice for a 2D image according to an embodiment. This device decodes anencoded stream of a 3D image encoded by the encoding device according tothe second embodiment.

In the constitution shown in FIG. 21, constitutions similar to theconstitutions in FIG. 15 are given similar reference numbers. The sameexplanation is omitted when appropriate.

The constitution of a decoding device 140 in FIG. 21 is different fromthe constitution in FIG. 15 in that a tile extraction unit 141 isprovided instead of the split unit 93, and that a screen rearrangementbuffer 142 is provided instead of the screen rearrangement buffer 95.

The tile extraction unit 141 splits encoded data into units of tilesbased on tile splittable information contained in VUI supplied by theextraction unit 92, and tile split information contained in SPS and PPS.The tile extraction unit 141 supplies encoded data of the tile #1included in encoded data of two tiles to the decoding unit 94-1. It isassumed herein that 2D display is performed by using the L image.However, the R image may be used for performing 2D display. In thiscase, not the encoded data of the tile #1, but the encoded data of thetile #2 is supplied to the decoding unit 94-1.

The screen rearrangement buffer 142 stores the decoded image of the tile#1 supplied by the decoding unit 94-1 for each unit of frames. Thescreen rearrangement buffer 142 rearranges the stored images for eachunit of frames located in the order for encoding in such positions thatthe images are located in the order of the original display, andsupplies the rearranged images to the D/A conversion unit 96.

Description of Process Performed by Decoding Device for 2D Image

FIG. 22 is a flowchart describing an encoded stream decoding processperformed by the decoding device 140 in FIG. 21.

The processing performed from steps S131 through S134 in FIG. 22 issimilar to the corresponding processing from step S61 through S64 inFIG. 18; therefore, the explanation of these steps is omitted.

In step S135, the tile extraction unit 141 supplies the encoded data ofthe tile #1 included in the encoded data of the split two tiles to thedecoding unit 94-1. In step S136, the decoding unit 94-1 performsdecoding in FIG. 19.

In step S137, the decoded image of the tile #1 supplied by the decodingunit 94-1 is stored for each unit of frames.

The processing in steps S138 and S139 is similar to the processing instep S68 and S69 in FIG. 18; therefore, the explanation of these stepsis omitted.

As discussed above, when the encoded stream is an encoded streamtile-split to provide different L image and R image and encoded,independent encoding of the L image and the R image is allowed.Accordingly, the decoding device 140 can decode only the encoded data ofthe L image of the tile #1 included in the decoding target encoded data.As a result, high-speed reproduction of a 2D image is realized. Inaddition, the decoding device 140 allows reduction of the capacity ofthe DPB, and reduction of power consumption at the time of decoding.

Similarly, when the encoded stream is an encoded stream tile-split intoa central area within the screen and into the other area, high-speedreproduction of only the central area to which attention is given isallowed.

Constitution Example of Decoding Device for 3D Image

A decoding device for 3D image shown in FIG. 20 for decoding a 3D imageencoded stream is a decoding device which sets N to 2 in FIG. 15. This3D image decoding device obtains a 3D image by independently decodingencoded data for an L image and for an R image, and synthesizing thedecoded data. Further, the decoding device for 3D image may beconstituted to output the L image and the R image obtained as a resultof the decoding without synthesizing these images.

In addition, while each of the L image and the R image is split into onetile according to the second embodiment, each of these images may besplit into a plurality of tiles. In other words, tiles may be split inany ways as long as the tiles are so split as not to contain both the Limage and R image.

Third Embodiment Constitution Example of Television Conference System

FIG. 23 is a block diagram showing a constitution example of atelevision conference system to which the present technique is appliedaccording to an embodiment.

A television conference system 160 in FIG. 23 is constituted by imagingdevices 161-1 through 161-M, encoding devices 162-1 through 162-M, asynthesizing device 163, decoding devices 164-1 through 164-M, anddisplay devices 165-1 through 165-M. The television conference system160 captures images of M participants of a conference positioned atdifferent locations, encodes and synthesizes the images, and decodes anddisplays the images.

More specifically, the imaging devices 161-1 through 161-M of thetelevision conference system 160 are positioned at the respectivelocations of the M participants of the conference. The imaging devices161-1 through 161-M capture images of the corresponding participants ofthe conference, and supply the images to the encoding devices 162-1through 162-M.

Each of the encoding devices 162-1 through 162-M has a constitutionsimilar to the structure of the encoding device 50 in FIG. 3. Theencoding devices 162-1 through 162-M compression-encode the imagessupplied by the imaging devices 161 independently for each tile by asystem corresponding to HEVC system. Each of the encoding devices 162-1through 162-M supplies an encoded stream obtained as a result of thecompression encoding to the synthesizing device 163.

The synthesizing device 163 receives the encoded streams transmittedfrom the encoding devices 162-1 through 162-M. The synthesizing device163 synthesizes each of encoded data contained in the synthesizedstreams as encoded data of different tiles. The synthesizing device 163generates tile split information indicating the positions of the encodeddata of the respective tiles and showing M as the number of splits fromthe encoded data obtained as a result of the synthesis. The synthesizingdevice 163 sets SPS containing tile split information and deblock filterinformation set to false (0). Moreover, the synthesizing device 163 setsVUI containing motion restriction information set to false (0), PPScontaining deblock filter information set to false (0), and APS. Thesynthesizing device 163 generates a synthesized stream by adding SPS,PPS, VUI, APS and the like to the encoded data obtained as a result ofthe synthesis. The synthesizing device 163 transmits the synthesizedstream to the decoding device 164-1 through 164-M.

Each of the decoding devices 164-1 through 164-M has a constitutionsimilar to the structure of the decoding device 90 in FIG. 15. Each ofthe decoding devices 164-1 through 164-M receives the synthesized streamtransmitted from the synthesizing device 163. Each of the decodingdevices 164-1 through 164-M independently decodes the synthesized streamfor each tile, and supplies the decoded image obtained as a result ofthe decoding to the corresponding one of the display devices 165-1through 165-M.

The respective display devices 165-1 through 165-M are disposed at thecorresponding locations of the M participants of the conference. Thedisplay devices 165-1 through 165-M display the decoded images suppliedby the decoding devices 164-1 through 164-M.

Further, according to the television conference system 160, the displaydevices 165-1 through 165-M are disposed at the corresponding locationsof the M participants of the conference. However, the display devicesmay be disposed at locations of a part of the M participants of theconference. In addition, the decoded images may be displayed on thedisplay devices of the persons not participating in the conference.

As discussed above, according to the television conference system 160,the encoding device 162-1 through 162-M perform encoding independentlyfor each tile. Accordingly, the motion vector in inter prediction alwaysbecomes a vector designating an image within a tile containing aprediction block as a reference image.

In this case, even when encoded data contained in encoded bit-streamssupplied by the encoding devices 162-1 through 162-M is synthesized bythe synthesizing device 163 as it is as a part of encoded data of onescreen, a decoded image corresponding to the encoded data of a differentencoding device after synthesis of the encoded data is not referred toat the time of decoding. In this case, normal decoding of the encodeddata after synthesis allowed. Accordingly, the synthesizing device 163can easily synthesize encoded bit-streams supplied by the encodingdevices 162-1 through 162-M without changing layers of Video CodingLayer (VCL) and lower layers.

This point is particularly advantageous for a television conferencesystem where the number of encoded bit-streams to be synthesized isdynamically changeable by addition of a new participant of theconference, or removal of a participant of the conference in the middleof the conference.

In addition, a decoded image of different encoded data is not referredto for each of the M encoded data contained in the synthesized stream.Accordingly, the synthesized stream can be again split into encodedstreams containing the respective encoded data. As a result, processingassociated with the synthesized stream is easily performed.

Further, according to the foregoing description, encoding and decodingare performed independently for each tile. However, encoding anddecoding may be performed independently for each slice.

Further, according to the foregoing description, the tile splittableinformation is collectively set for all the tiles constituting apicture. However, the tile splittable information may be individuallyset for each tile.

Another Example of VUI

FIG. 24 is a diagram showing another example of syntax of VUI when thetile splittable information is set for each tile.

When the tile splittable information is set for each tile, tilesplittable information (tile_splittable_flag) of respective tilesarranged in the line direction (horizontal direction) is set for eachline in VUI as shown in lines 5 through 7 in FIG. 24.

In this case, encoding and decoding can be performed only for apredetermined tile for each unit of tiles contained in the tilesconstituting a picture. For example, assuming that the number of tilesis 4, with the tile splittable information of the tile #1 set to true(1) and with the tile splittable information of the tiles #2 through #4set to false (0), independent decoding of only the tile #1 is allowed.

Further, when bitstream_restriction_flag for line 1 is 0, the decodingside recognizes that all the tiles are not decodable for each tile basedon the determination that the tile splittable information for all thetiles is set to false (0).

Fourth Embodiment Applicability to Multi-view Image Encoding andMulti-View Image Decoding

A series of processes described above are applicable to multi-view imageencoding and multi-view image decoding. FIG. 25 shows an example ofmulti-view image encoding system.

As shown in FIG. 25, a multi-view image contains images of a pluralityof views (views). The plural views of the multi-view image areconstituted by base views for encoding and decoding using only images oftheir own views without using images of other views, and non-base viewsfor encoding and decoding using images of other views. The non-baseviews may use images of base views, or may use images of other non-baseviews.

For encoding and decoding a multi-view image as shown in FIG. 25, imagesof the respective views are encoded or decoded. In this case, themethods in the first through third embodiments described above may beapplied to encoding and decoding of the respective views. When thesemethods are applied, independent encoding and decoding in the timedirection for each tile is allowed.

Moreover, the flags and parameters used in the methods according to thefirst through third embodiments described above may be shared inencoding and decoding the respective views. More specifically, syntaxelements or the like of SPS, PPS, VUI, and APS may be shared in encodingand decoding of the respective views, for example. Needless to say,necessary information other than these may be shared in encoding anddecoding of the respective views.

When these are shared, suppression of redundant informationtransmission, and reduction of the amount of information (amount ofcodes) to be transmitted are achieved (that is, lowering of encodingefficiency is suppressed).

Multi-View Image Encoding Device

FIG. 26 is a diagram showing a multi-view image encoding device whichperforms the foregoing multi-view image encoding. As shown in FIG. 26, amulti-view image encoding device 600 includes an encoding unit 601, anencoding unit 602, and a multiplexing unit 603.

The encoding unit 601 encodes base view images, and generates a baseview image encoded stream. The encoding unit 602 encodes non-base viewimages, and generates a non-base view image encoded stream. Themultiplexing unit 603 multiplexes the base view image encoded streamgenerated by the encoding unit 601 and the non-base view image encodedstream generated by the encoding unit 602, and generates a multi-viewimage encoded stream.

The encoding device 50 (FIG. 3), and the encoding devices 162-1 through162-M (FIG. 23) are applicable to the encoding unit 601 and the encodingunit 602 of this multi-view image encoding device 600. In other words,in encoding the respective views, independent encoding in the timedirection for each tile is allowed. Moreover, the encoding unit 601 andthe encoding unit 602 can perform encoding using the same flags andparameters (e.g., syntax elements associated with processing betweenimages) (that is, flags and parameters can be shared between theencoding units 601 and 602). Accordingly, lowering of the encodingefficiency can be suppressed.

Multi-View Image Decoding Device

FIG. 27 is a diagram showing a multi-view decoding device performing theforegoing multi-view image decoding. As shown in FIG. 27, a multi-viewimage decoding device 610 has an inverse multiplexing unit 611, adecoding unit 612, and a decoding unit 613.

The inverse multiplexing unit 611 performs inverse multiplexing of themulti-view image encoded stream generated by multiplexing of the baseview image encoded stream and the non-base view image encoded stream,and extracts the base view image encoded stream and the non-base viewimage encoded stream. The decoding unit 612 decodes the base view imageencoded stream extracted by the inverse multiplexing unit 611, andobtains base view images. The decoding unit 613 decodes the non-baseview image encoded stream extracted by the inverse multiplexing unit611, and obtains non-base view images.

The decoding device 90 (FIG. 15), and the decoding device 140 (FIG. 21)or the decoding devices 164-1 through 164-M (FIG. 23) are applicable tothe decoding unit 612 and the decoding unit 613 of this multi-view imagedecoding device 610. In other words, in decoding the respective views,independent decoding in the time direction for each tile is allowed.Moreover, the decoding unit 612 and the decoding unit 613 can performdecoding using the same flags and parameters (e.g., syntax elementsassociated with processing between images) (that is, flags andparameters can be shared between the decoding units 612 and 613).Accordingly, lowering of the encoding efficiency can be suppressed.

Fifth Embodiment Applicability to Hierarchical Image Encoding andHierarchical Image Decoding

A series of processes described above are applicable to hierarchicalimage encoding and hierarchical image decoding (scalable encoding andscalable decoding). FIG. 28 shows an example of hierarchical imageencoding system.

Hierarchical image encoding (scalable encoding) divides image data intoa plurality of layers (hierarchies) such that a predetermined parameterhas a scalability function, and encodes each layer. Hierarchical imagedecoding (scalable decoding) is decoding in correspondence with thishierarchical image encoding.

As shown in FIG. 28, in layering images, one image is divided into aplurality of images (layers) on the basis of a predetermined parameterhaving a scalability function. In other words, the hierarchized image(hierarchical image) contains a plurality of hierarchies (layers) ofimages each having a parameter value different from one another in viewof the predetermined parameter. These plural layers of the hierarchicalimage are constituted by base layers for encoding and decoding usingonly images of their own layers without using images of other layers,and non-base layers (also called enhancement layers) for encoding anddecoding using images of other layers. The non-base layers may useimages of base layers, or may use images of other non-base layers.

In general, the non-base layers are constituted by data (differencedata) of difference images between their own images and images of otherlayers for reduction of redundancy. For example, when one image isdivided into two hierarchies of a base layer and a non-base layer (alsocalled enhancement layer), an image having lower quality than that ofthe original image is formed based on only data of the base layer. Onthe other hand, the original image (i.e., high-quality image) can beformed when data of the base layer and data of the non-base layer aresynthesized.

When an image is hierarchized in this way, the quality of the image canbe easily varied depending on situations. For example, in case of aterminal having low processing ability such as a cellular phone, imagecompression information of only base layers is transmitted to form adynamic image having low spatiotemporal resolution or having low imagequality, for example. In case of a terminal having high processingability such as a television and a personal computer, image compressioninformation of enhancement layers in addition to base layers istransmitted to form a dynamic image having high spatiotemporalresolution or having high quality, for example. In this case, imagecompression information in accordance with the ability of the terminalor network can be transmitted from the server without executingtranscode processing.

In encoding and decoding the hierarchical image as shown in the examplein FIG. 28, the images of the respective layers are encoded and decoded.In this case, the methods according to the first through thirdembodiments are applicable to encoding and decoding of the respectivelayers. When these methods are applied, independent encoding anddecoding in the time direction for each tile is allowed.

Moreover, the flags and parameters used in the methods according to thefirst through third embodiments described above may be shared inencoding and decoding of the respective layers. More specifically,syntax elements or the like of SPS, PPS, VUI, and APS may be shared inencoding and decoding of the respective layers, for example. Needless tosay, necessary information other than these may be shared in encodingand decoding of the respective layers.

When these are shared, suppression of redundant informationtransmission, and reduction of the amount of information (amount ofcodes) to be transmitted can be achieved (that is, lowering of encodingefficiency can be suppressed).

Scalable Parameter

According to these hierarchical image encoding and hierarchical imagedecoding (scalable encoding and scalable decoding), the parameter havingscalability (scalability) function is an arbitrary parameter. Forexample, the spatial resolution shown in FIG. 29 may be determined asthe parameter (spatial scalability). In case of the spatial scalability(spatial scalability), the resolution of the image is variable for eachlayer. More specifically, in this case, each picture is divided into twotypes of hierarchies of base layers having lower spatial resolution thanthe resolution of the original image, and enhancement layers obtainingthe original spatial resolution when synthesized with the base layers asshown in FIG. 29. Needless to say, this number of hierarchies is anexample, and the number of hierarchies may be an arbitrary number.

Alternatively, the parameter having this scalability may be temporalresolution (temporal scalability) as shown in FIG. 30, for example. Incase of this temporal scalability (temporal scalability), the frame rateis variable for each layer. More specifically, in this case, eachpicture is divided into two types of hierarchies of base layers having alower frame rate than the frame rate of the original image, andenhancement layers obtaining the original frame rate when synthesizedwith the base layers as shown in FIG. 30. Needless to say, this numberof hierarchies is an example, and the number of hierarchies may be anarbitrary number.

Moreover, the parameter having this scalability may be a signal to noiseratio (Signal to Noise ratio (SNR)) (SNR scalability), for example. Incase of this SNR scalability, the SNR ratio is variable for each layer.More specifically, in this case, each picture is divided into two typesof hierarchies of base layers having a lower SNR than the SNR of theoriginal image, and enhancement layers obtaining the original SNR whensynthesized with the base layers as shown in FIG. 31. Needless to say,this number of hierarchies is an example, and the number of hierarchiesmay be an arbitrary number.

Obviously, the parameter having scalability may be a parameter otherthan the foregoing parameters. For example, the parameter havingscalability may be a bit depth (bit-depth scalability). In case of thisbit-depth scalability, the bit depth is variable for each layer. In thiscase, each of base layers is constituted by an 8-bit image, for example.An enhancement layer is added to this image so as to obtain a 10-bit(bit) image.

In addition, the parameter having scalability may be a chroma format(chroma scalability). In case of this chroma scalability, the chromaformat is variable for each layer. In this case, each of base layers(base layers) is constituted by a component image having 4:2:0 format,for example. An enhancement layer is added to this layer so as to obtaina component image having 4:2:2 format.

Hierarchical Image Encoding Device

FIG. 32 shows a hierarchical image encoding device which performs theforegoing hierarchical image encoding. As shown in FIG. 32, ahierarchical image encoding device 620 includes an encoding unit 621, anencoding unit 622, and a multiplexing unit 623.

The encoding unit 621 encodes base layer images, and generates a baselayer image encoded stream. The encoding unit 622 encodes non-base layerimages, and generates a non-base layer image encoded stream. Themultiplexing unit 623 multiplexes the base layer image encoded streamgenerated by the encoding unit 621 and the non-base layer image encodedstream generated by the encoding unit 622, and generates a hierarchicalimage encoded stream.

The encoding device 50 (FIG. 3), and the encoding devices 162-1 through162-M (FIG. 23) are applicable to the encoding unit 621 and the encodingunit 622 of this hierarchical image encoding device 620. In other words,in encoding the respective layers, independent encoding in the timedirection for each tile is allowed. Moreover, the encoding unit 621 andthe encoding unit 622 can perform control of filtering for intraprediction and the like using the same flags and parameters (e.g.,syntax elements associated with processing between images) (that is,flags and parameters can be shared between the encoding units 621 and622). Accordingly, lowering of the encoding efficiency can besuppressed.

Hierarchical Image Decoding Device

FIG. 33 is a diagram showing a hierarchical image decoding device whichperforms the foregoing hierarchical image decoding. As shown in FIG. 33,a hierarchical image decoding device 630 includes an inversemultiplexing unit 631, a decoding unit 632, and a decoding unit 633.

The inverse multiplexing unit 631 performs inverse multiplexing of thehierarchical image encoded stream generated by multiplexing of the baselayer image encoded stream and the non-base layer image encoded stream,and extracts the base layer image encoded stream and the non-base layerimage encoded stream. The decoding unit 632 decodes the base layer imageencoded stream extracted by the inverse multiplexing unit 631, andobtains base layer images. The decoding unit 633 decodes the non-baselayer image encoded stream extracted by the inverse multiplexing unit631, and obtains non-base layer images.

The decoding device 90 (FIG. 15), the decoding device 140 (FIG. 21), orthe decoding devices 164-1 through 164-M (FIG. 23) are applicable to thedecoding unit 632 and the decoding unit 633 of this hierarchical imagedecoding device 630. In other words, in decoding the respective layers,independent decoding in the time direction for each tile is allowed.Moreover, the decoding unit 612 and the decoding unit 613 can performdecoding using the same flags and parameters (e.g., syntax elementsassociated with processing between images) (that is, flags andparameters can be shared between the decoding units 612 and 613).Accordingly, lowering of the encoding efficiency can be suppressed.

Sixth Embodiment Description of Computer to which this Technique isApplied

A series of the foregoing processes may be executed by hardware, or maybe executed by software. When the series of the processes are executedby software, a program constituting the software is installed in acomputer. Examples of this computer include a computer incorporated indedicated hardware, and a general-purpose computer or the like capableof executing various types of functions under various types of programsinstalled therein.

FIG. 34 is a block diagram showing a constitution example of hardware ofa computer executing the series of the foregoing processes under aprogram.

In the computer, a Central Processing Unit (CPU) 801, a Read Only Memory(ROM) 802, and a Random Access Memory (RAM) 803 are connected with eachother via a bus 804.

An input/output interface 805 is further connected with the bus 804. Aninput unit 806, an output unit 807, a storage unit 808, a communicationunit 809, and a drive 810 are connected with the input/output interface805.

The input unit 806 is constituted by a keyboard, a mouse, a microphoneand the like. The output unit 807 is constituted by a display, a speakerand the like. The storage unit 808 is constituted by a hard disk, anon-volatile memory and the like. The communication unit 809 isconstituted by a network interface and the like. The drive 810 drives aremovable medium 811 in the form of a magnetic disk, an optical disk, amagneto-optical disk, a semiconductor memory or the like.

According to the computer thus constituted, the series of the foregoingprocesses are performed by the CPU 801 which loads the program stored inthe storage unit 808 to the RAM 803 via the input/output interface 805and the bus 804, and executes the program, for example.

The program executed by the computer (CPU 801) can be recorded on theremovable medium 811 as a package medium or the like, and provided inthe form of the removable medium 811, for example. In addition, theprogram can be provided via a wired or wireless transmission medium suchas a local area network, the Internet, and digital satellitebroadcasting.

According to the computer, the program can be installed into the storageunit 808 from the removable medium 811 attached to the drive 810 via theinput/output interface 805. Alternatively, the program can be receivedby the communication unit 809 via a wired or wireless transmissionmedium, and installed into the storage unit 808. Instead, the programcan be installed beforehand in the ROM 802 or the storage unit 808.

Further, the program to be executed by the computer may be a programunder which processes are performed in time series in the orderdescribed in this specification, or performed in parallel, or at thetime of necessity such as at the time of accesses.

Seventh Embodiment Constitution Example of Television Set

FIG. 35 shows an example of the general structure of a television set towhich the present technique is applied. A television set 900 includes anantenna 901, a tuner 902, a demultiplexer 903, a decoder 904, a videosignal processing unit 905, a display unit 906, an audio signalprocessing unit 907, a speaker 908, and an external interface unit 909.The television set 900 further includes a control unit 910, a userinterface unit 911, and the like.

The tuner 902 selects a desired channel from broadcast wave signalsreceived by the antenna 901, demodulates the selected channel, andoutputs an encoded bit-stream thus obtained to the demultiplexer 903.

The demultiplexer 903 extracts a packet of pictures and voice of aprogram to be watched from the encoded bit-stream, and outputs the dataof the extracted packet to the decoder 904. In addition, thedemultiplexer 903 supplies a packet of data such as Electronic ProgramGuide (EPG) to the control unit 910. At the time of scrambling,scrambling is cancelled by using a demultiplexer or the like.

The decoder 904 performs decoding of the packet, and outputs video datagenerated by decoding to the video signal processing unit 905, andoutputs audio data to the audio signal processing unit 907.

The video signal processing unit 905 performs processing of the videodata such as noise removal, picture processing and the like inaccordance with user settings. The video signal processing unit 905generates image data of the program to be displayed on the display unit906, image data produced by processing performed under an applicationsupplied via a network, and the like. In addition, the video signalprocessing unit 905 generates video data for displaying a menu screenallowing selection of items or the like, and superimposes the generatedvideo data on the video data of the program. The video signal processingunit 905 generates driving signals based on the video data thusgenerated, and drives the display unit 906.

The display unit 906 drives display devices (such as liquid crystaldisplay elements) in accordance with the driving signals received fromthe video signal processing unit 905 to display pictures and the like ofthe program.

The audio signal processing unit 907 executes predetermined processingof audio data such as noise removal, performs D/A conversion andamplification of the audio data after the processing, and supplies theresult to the speaker 908 to output voice.

The external interface unit 909 is an interface connecting with anexternal device or a network. The external interface unit 909 transmitsand receives data such as video data and audio data.

The user interface unit 911 is connected with the control unit 910. Theuser interface unit 911 is constituted by an operation switch, a remotecontrol signal receiving unit and the like, and supplies operationsignals corresponding to user operation to the control unit 910.

The control unit 910 is constituted by a Central Processing Unit (CPU),a memory and the like. The memory stores a program executed by the CPU,various types of data necessary for processing performed by the CPU, EPGdata, data obtained via a network, and the like. The program stored inthe memory is read and executed by CPU at a predetermined time such asthe start of the television set 900. The CPU controls the respectiveparts by executing the program such that the television set 900 operatesin accordance with user operation.

Further, the television set 900 is provided with a bus 912 through whichthe control unit 910 connects with the tuner 902, the demultiplexer 903,the video signal processing unit 905, the audio signal processing unit907, the external interface unit 909 and the like.

According to the television set thus constituted, the decoder 904 isprovided with the function of the decoding device (decoding method) ofthe present application. Accordingly, independent decoding in the timedirection for each tile is allowed.

Eighth Embodiment Constitution Example of Cellular Phone

FIG. 36 shows an example of the general structure of a cellular phone towhich the present technique is applied. A cellular phone 920 includes acommunication unit 922, an audio codec 923, a camera unit 926, an imageprocessing unit 927, a multiplexing split unit 928, a recording andreproducing unit 929, a display unit 930, and a control unit 931. Theseare connected with each other via a bus 933.

An antenna 921 is connected with the communication unit 922, while aspeaker 924 and a microphone 925 are connected with the audio codec 923.Moreover, an operation unit 932 is connected with the control unit 931.

The cellular phone 920 performs various types of operations such astransmission and reception of audio signals, transmission and receptionof e-mails and image data, imaging, data recording and the like invarious types of modes including audio communication mode and datacommunication mode.

In the audio communication mode, audio signals generated by themicrophone 925 are converted into audio data and are subjected to datacompression by the audio codec 923, and supplied to the communicationunit 922. The communication unit 922 performs modulation, frequencytransformation and other processing of the audio data, and generatestransmission signals. In addition, the communication unit 922 suppliesthe transmission signals to the antenna 921 to transmit the transmissionsignals to a not-shown base station. Moreover, the communication unit922 performs amplification, frequency transformation, demodulation andother processing of reception signals received by the antenna 921, andsupplies audio data thus obtained to the audio codec 923. The audiocodec 923 expands data of the audio data, and converts the audio datainto analog audio signals, and outputs the result to the speaker 924.

In addition, for mail transmission in the data communication mode, thecontrol unit 931 receives character data inputted by operation of theoperation unit 932, and displays the inputted characters on the displayunit 930. Moreover, the control unit 931 generates mail data based onuser instructions or the like through the operation unit 932, andsupplies the data to the communication unit 922. The communication unit922 performs modulation, frequency transformation and the like of themail data, and transmits transmission signal thus obtained via theantenna 921. Furthermore, the communication unit 922 performsamplification, frequency transformation, demodulation and the like ofreception signals received by the antenna 921 to restore the mail data.The mail data thus obtained is supplied to the display unit 930 todisplay the contents of the mail.

Further, the cellular phone 920 can store the received mail data in amemory medium using the recording and reproducing unit 929. The memorymedium is an arbitrary rewritable memory medium. For example, the memorymedium is a removable medium such as a semiconductor memory including aRAM and a built-in flash memory, a hard disk, a magnetic disk, amagneto-optical disk, an optical disk, a USB memory, and a memory card.

For transmitting image data in the data communication mode, image datagenerated by the camera unit 926 is supplied to the image processingunit 927. The image processing unit 927 performs encoding of the imagedata to generate encoded data.

The multiplexing split unit 928 multiplexes the encoded data generatedby the image processing unit 927, and the audio data supplied by theaudio codec 923 by a predetermined system, and supplies the result tothe communication unit 922. The communication unit 922 performsmodulation, frequency transformation and the like of the multiplexeddata, and transmits transmission signals thus obtained to the antenna921. In addition, the communication unit 922 performs amplification,frequency transformation, demodulation and the like of reception signalsreceived by the antenna 921 to restore the multiplexed data. Thismultiplexed data is supplied to the multiplexing split unit 928. Themultiplexing split unit 928 splits the multiplexed data, and suppliesthe encoded data to the image processing unit 927, and supplies theaudio data to the audio codec 923. The image processing unit 927performs decoding of the encoded data to generate image data. This imagedata is supplied to the display unit 930 to display images thusreceived. The audio codec 923 converts the audio data into analog audiosignals, and supplies the result to the speaker 924 to output voice thusreceived.

According to the cellular phone thus constituted, the image processingunit 927 is provided with the functions of the encoding device and thedecoding device (encoding method and decoding method) according to thepresent application. Accordingly, independent encoding and decoding inthe time direction for each tile are allowed.

Ninth Embodiment Constitution Example of Recording and ReproducingDevice

FIG. 37 shows an example of the general structure of a recording andreproducing device to which the present technique is applied. Arecording and reproducing device 940 records audio data and video dataof a received broadcast program on a recording medium, and provides therecorded data to a user at a time corresponding to instructions of theuser, for example. In addition, the recording and reproducing device 940can obtain audio data and video data from another device, and recordthese on a recording medium, for example. Furthermore, the recording andreproducing device 940 can achieve image display and voice output from amonitoring device or the like by decoding audio data and video datarecorded on a recording medium and outputting the result.

The recording and reproducing device 940 includes a tuner 941, anexternal interface unit 942, an encoder 943, a Hard Disk Drive (HDD)unit 944, a disk drive 945, a selector 946, a decoder 947, an On-ScreenDisplay (OSD) unit 948, a control unit 949, and a user interface unit950.

The tuner 941 selects a desired channel from broadcast signals receivedby a not-shown antenna. The tuner 941 outputs an encoded bit-streamobtained by demodulating reception signals of the desired channel to theselector 946.

The external interface unit 942 is constituted by at least any of anIEEE 1394 interface, a network interface unit, a USB interface, a flashmemory interface and the like. The external interface unit 942 is aninterface for connection with an external device, a network, a memorycard or the like, and receives data to be recorded such as video dataand audio data.

The encoder 943 performs encoding by a predetermined system when thevideo data and audio data supplied by the external interface unit 942are not encoded, and outputs an encoded bit-stream to the selector 946.

The HDD unit 944 records contents data such as pictures and voice,various types of programs, other data and the like on a built-in harddisk, and reads these from the corresponding hard disk at the time ofreproduction, for example.

The disk drive 945 records signals on an attached optical disk, andreproduces signals from the optical disk. The optical disk is a DVD disk(DVD-Video, DVD-RAM, DVD-RW, DVD+R, DVD+RW, for example), Blu-ray(registered trademark) disk, or the like.

The selector 946 selects any of the encoded bit-streams from the tuner941 or the encoder 943 at the time of recording of pictures or voice,and supplies the selected bit-stream to either the HDD unit 944 or thedisk drive 945. In addition, the selector 946 supplies the encodedbit-stream outputted from the HDD unit 944 or the disk drive 945 to thedecoder 947.

The decoder 947 performs decoding of the encoded bit-stream. The decoder947 supplies video data generated by decoding to the OSD unit 948. Inaddition, the decoder 947 outputs audio data generated by decoding.

The OSD unit 948 generates video data for displaying a menu screenassociated with selection of items or the like, superimposes the videodata on video data outputted from the decoder 947, and outputs theresult.

The user interface unit 950 is connected with the control unit 949. Theuser interface unit 950 is constituted by an operation switch, a remotecontrol signal receiving unit and the like, and supplies operationsignals corresponding to user operation to the control unit 949.

The control unit 949 is constituted by a CPU, a memory and the like. Thememory stores a program executed by the CPU and various data necessaryfor processing performed by the CPU. The program stored in the memory isread and executed by the CPU at a predetermined time such as the startof the recording and reproducing device 940. The CPU controls therespective parts by executing the program such that the recording andreproducing device 940 operates in accordance with user operation.

According to the recording and reproducing device thus constituted, thedecoder 947 is provided with the function of the decoding device(decoding method) according to the present application. Accordingly,independent decoding in the time direction for each tile is allowed.

Tenth Embodiment Constitution Example of Imaging Device

FIG. 38 shows an example of the general structure of an imaging deviceto which the present technique is applied. An imaging device 960 imagesan object, and displays an image of the object on a display unit, andrecords the image on a recording medium as image data.

The imaging device 960 includes an optical block 961, an imaging unit962, a camera signal processing unit 963, an image data processing unit964, a display unit 965, an external interface unit 966, a memory unit967, a media drive 968, an OSD unit 969, and a control unit 970.Moreover, a user interface unit 971 is connected with the control unit970. Furthermore, the image data processing unit 964, the externalinterface unit 966, the memory unit 967, the media drive 968, the OSDunit 969, the control unit 970 and the like are connected with oneanother via a bus 972.

The optical block 961 is constituted by a focus lens, a diaphragmmechanism and the like. The optical block 961 forms an optical image ofan object on an imaging surface of the imaging unit 962. The imagingunit 962 is constituted by a CCD or CMOS image sensor. The imaging unit962 generates electric signals in correspondence with the optical imageby photoelectric conversion, and supplies the electric signals to thecamera signal processing unit 963.

The camera signal processing unit 963 performs various types of camerasignal processing, such as knee correction, gamma correction, and colorcorrection, for the electric signals supplied by the imaging unit 962.The camera signal processing unit 963 supplies the image data aftercamera signal processing to the image data processing unit 964.

The image data processing unit 964 performs encoding of the image datasupplied by the camera signal processing unit 963. The image dataprocessing unit 964 supplies encoded data generated by encoding to theexternal interface unit 966 and the media drive 968. In addition, theimage data processing unit 964 performs decoding of the encoded datasupplied by the external interface unit 966 and the media drive 968. Theimage data processing unit 964 supplies image data generated by decodingto the display unit 965. Furthermore, the image data processing unit 964supplies image data supplied by the camera signal processing unit 963 tothe display unit 965. In addition, the image data processing unit 964superimposes display data received from the OSD unit 969 on image dataand supplies the result to the display unit 965.

The OSD unit 969 generates display data such as a menu screen and iconsin the form of symbols, characters, or figures, and outputs the displaydata to the image data processing unit 964.

The external interface unit 966 is constituted by a USB input/outputterminal and the like, and connected with a printer at the time ofprinting of images. In addition, a drive is connected with the externalinterface unit 966 as necessary. A computer program is read from aremovable medium, such as a magnetic disk and an optical disk,appropriately attached to the drive, and the computer program read fromthe medium is installed as necessary. Moreover, the external interfaceunit 966 has a network interface connected with a predetermined networksuch as a LAN and the Internet. The control unit 970 can read encodeddata from the memory unit 967 in accordance with instructions from theuser interface unit 971, for example, and allow the external interfaceunit 966 to supply the data to another device connected via the network.Furthermore, the control unit 970 allows the external interface unit 966to obtain encoded data and image data supplied by another device via thenetwork, and supplies the data to the image data processing unit 964.

The recording medium driven by the media drive 968 is a magnetic disk, amagneto-optical disk, an optical disk, a semiconductor memory, or otherarbitrary readable and writable removable medium, for example. Inaddition, the recording medium may be an arbitrary type of removablemedium, such as a tape device, a disk, and a memory card. Needless tosay, the recording medium may be a non-contact IC card or the like.

Moreover, the media drive 968 and the recording medium may be unified,and constituted by a non-portable recording medium such as a built-inhard disk drive and a Solid State Drive (SSD).

The control unit 970 is constituted by a CPU, a memory and the like. Thememory stores a program executed by the CPU and various types of datanecessary for processing performed by the CPU, for example. The programstored in the memory is read and executed by the CPU at a predeterminedtime such as the start of the imaging device 960. The CPU controls therespective parts by executing the program such that the imaging device960 operates in accordance with user operations.

According to the imaging device thus constituted, the image dataprocessing unit 964 is provided with the functions of the encodingdevice and the decoding device (encoding method and decoding method)according to the present application. Accordingly, independent encodingand decoding for each tile are allowed.

Application Example of Scalable Encoding First System

A specific application example of scalable encoded data after scalableencoding (hierarchical encoding) is now described. For example, scalableencoding is used for selection of data to be transmitted as an exampleshown in FIG. 39.

In a data transmission system 1000 shown in FIG. 39, a distributionserver 1002 reads scalable encoded data stored in a scalable encodeddata memory unit 1001, and distributes the data to terminal devices suchas a personal computer 1004, an AV device 1005, a tablet device 1006,and a cellular phone 1007 via a network 1003.

At this time, the distribution server 1002 selects and transmits encodeddata having an appropriate quality in accordance with the capacities,communication environments and the like of the terminal devices. Whenthe quality of the data transmitted from the distribution server 1002 isexcessively high, high-quality images are not necessarily produced bythe terminal devices. In this condition, there is a possibility of delayor overflow, and further a possibility of unnecessary occupation of thecommunication bands or unnecessary increase in loads on the terminaldevices. In contrast, when the quality of the data transmitted from thedistribution server 1002 is excessively low, images having sufficientquality may be difficult to be produced by the terminal devices.Accordingly, the distribution server 1002 reads scalable encoded datastored in the scalable encoded data memory unit 1001 as encoded datahaving quality appropriate for the capacities, environments and the likeof the terminal devices, and transmits the data appropriately.

For example, it is assumed that the scalable encoded data memory unit1001 stores scalable encoded data (BL+EL) 1011 obtained by scalableencoding. The scalable encoded data (BL+EL) 1011 is encoded datacontaining both base layers and enhancement layers, and produces bothbase layer images and enhancement layer images when decoded.

The distribution server 1002 selects appropriate layers in accordancewith capacities, communication environments and the like of the terminaldevices to which data is transmitted, and reads data of the selectedlayers. For example, the distribution server 1002 reads high-qualityscalable encoded data (BL+EL) 1011 from the scalable encoded data memoryunit 1001, and transmits the data as it is to the personal computer 1004and the tablet device 1006 having high processing ability. On the otherhand, for example, the distribution server 1002 extracts data of baselayers from the scalable encoded data (BL+EL) 1011, and transmits theextracted data as scalable data (BL) 1012 having the same contents asthe contents of the scalable encoded data (BL+EL) 1011 but having lowerquality than the quality of the scalable encoded data (BL+EL) 1011 tothe AV device 1005 and the cellular phone 1007 having lower processingability.

As can be understood, the amount of data can be easily controlled by theuse of the scalable encoded data. Accordingly, the possibility of delayand overflow, and further the possibility of unnecessary increase inloads on the terminal devices and communication media can be suppressed.Moreover, in case of the scalable encoded data (BL+EL) 1011, theredundancy between layers is reduced; therefore, the amount of databecomes smaller in comparison with the case when the encoded data of therespective layers is handled as discrete data. Accordingly, the memoryarea of the scalable encoded data memory unit 1001 can be moreefficiently utilized.

Further, the terminal devices may be various types of devices includingthe personal computer 1004 through the cellular phone 1007. Thus, theperformance of the hardware is variable according to the types of thedevices. Moreover, the applications to be executed by the terminaldevices are of various types; therefore, the capacity of the software isalso variable. Furthermore, the network 1003 functioning as acommunication medium may be various types of communication networksincluding wired, wireless, and both wired and wireless types such as theInternet and a Local Area Network (LAN). Thus, the data transmissioncapacity is variable. In addition, variations may be produced by othercommunications, for example.

Accordingly, the distribution server 1002 may communicate with theterminal devices corresponding to the data transmission destinationsbefore starting data transmission so as to obtain information about thecapacities of the terminal devices such as the hardware performance ofthe terminal devices, the capacity of the application (software)executed by the terminal devices, and information about thecommunication environments such as the usable band range of the network1003. Then, the distribution server 1002 may select the appropriatelayers based on the information thus obtained.

Further, extraction of layers may be performed by the terminal devices.For example, the personal computer 1004 may decode the transmittedscalable encoded data (BL+EL) 1011, and display images of base layers,or display images of enhancement layers. In addition, the personalcomputer 1004 may extract the scalable encoded data (BL) 1012 of baselayers from the transmitted scalable encoded data (BL+EL) 1011, storethe data 1012, transfer the data 1012 to another device, and decode thedata 1012 to display images of base layers, for example.

Needless to say, each number of the scalable encoded data memory unit1001, the distribution server 1002, the network 1003, and the terminalsis an arbitrary number. In addition, while the example in which thedistribution server 1002 transmits data to the terminal devices has beendiscussed herein, application examples are not limited to this example.The data transmission system 1000 is applicable to any system as long asthe system selects appropriate layers in accordance with the capacitiesof the terminal devices, communication environment and the like andtransmits the selected layers when transmitting encoded data afterscalable encoding to the terminal devices.

Second System

Moreover, scalable encoding is applicable to transmission via aplurality of communication media as in an example shown in FIG. 40, forexample.

In a data transmission system 1100 shown in FIG. 40, a broadcastingstation 1101 transmits scalable encoded data (BL) 1121 of base layers1121 through ground wave broadcast 1111. Moreover, the broadcastingstation 1101 transmits (e.g., transmits in the form of packets) scalableencoded data (EL) 1122 of enhancement layers via an arbitrary network1112 constituted by a wired, wireless, or both wired and wirelesscommunication network.

A terminal device 1102 is provided with the function of receiving theground wave broadcast 1111 broadcasted by the broadcasting station 1101,and receives the scalable encoded data (BL) 1121 of base layerstransmitted via the ground wave broadcast 1111. In addition, theterminal device 1102 further has the communication function of providingcommunication via the network 1112, and receives the scalable encodeddata (EL) 1122 of enhancement layers transmitted via the network 1112.

The terminal device 1102 decodes the scalable encoded data (BL) 1121 ofbase layers obtained via the ground wave broadcast 1111 in accordancewith user instructions or the like, for example, and obtains images ofbase layers, stores the images, and transmits the images to anotherdevice.

Moreover, the terminal device 1102 synthesizes the scalable encoded data(BL) 1121 of base layers obtained via the ground wave broadcast 1111 andthe scalable encoded data (EL) 1122 obtained via the network 1112 inaccordance with user instructions or the like, for example, to obtainscalable encoded data (BL+EL), obtains images of enhancement layers bydecoding of the data, stores the images, and transmits the images toanother device.

As described above, the scalable encoded data can be transmitted viatransmission media different for each layer, for example. Accordingly,loads can be dispersed, and the possibility of delay and overflow can besuppressed.

Furthermore, the communication medium to be used for transmission may beselected for each layer depending on situations. For example, thescalable encoded data (BL) 1121 of base layers having a relatively largeamount of data may be transmitted via a communication medium having awide band range, while the scalable encoded data (EL) 1122 ofenhancement layers having a relatively small amount of data may betransmitted through a communication medium having a narrow band range.In addition, for example, the communication medium transmitting thescalable encoded data (EL) 1122 of enhancement layers may be switchedbetween the network 1112 and the ground wave broadcast 1111 inaccordance with the usable band range of the network 1112. Needless tosay, this applies to data of arbitrary layers.

This control can further suppress increase in loads imposed on datatransmission.

Obviously, the number of layers is an arbitrary number, and the numberof the communication media to be used for transmission is also anarbitrary number. Moreover, the number of the terminal device 1102 asdata distribution target is also an arbitrary number. Furthermore, whilethe example of broadcasting from the broadcasting station 1101 has beendiscussed, application examples are not limited to this example. Thedata transmission system 1100 is applicable to an arbitrary system aslong as the system splits encoded data after scalable encoding into aplurality of parts of layer units and transmits the data via a pluralityof lines.

Third System

Moreover, scalable encoding is applicable to storage of encoded data asan example shown in FIG. 41.

In an imaging system 1200 shown in FIG. 41, an imaging device 1201performs scalable-encoding of image data obtained by imaging an object1211, and supplies the data to a scalable encoded data storage device1202 as scalable encoded data (BL+EL) 1221.

The scalable encoded data storage device 1202 stores the scalableencoded data (BL+EL) 1221 supplied from the imaging device 1201 as datahaving quality in accordance with situations. For example, in the normalcondition, the scalable encoded data storage device 1202 extracts dataof base layers from the scalable encoded data (BL+EL) 1221, and storesthe data as scalable encoded data (BL) 1222 of base layers having lowquality and a small amount of data. On the other hand, in the attentioncondition, for example, the scalable encoded data storage device 1202stores the scalable encoded data (BL+EL) 1221 as it is as data havinghigh quality and a large amount of data.

By this method, the scalable encoded data storage device 1202 can storeimages having high quality only as necessary. Accordingly, this methodsuppresses increase in the amount of data while suppressing lowering ofvalues of images caused by deterioration of image quality. As a result,the utilization efficiency of the memory area can improve.

For example, it is assumed herein that the imaging device 1201 is amonitoring camera. When a monitoring target (such as invader) is notpresent in a captured image (i.e., in the normal condition), thepossibility that the contents of the captured image are not important ishigh. In this case, reduction of the amount of data has priority, andthe image data (scalable encoded data) is stored as low quality data. Onthe other hand, when the monitoring target is present in a capturedimage as the object 1211 (i.e., in the attention condition), thepossibility that the contents of the captured image are important ishigh. Accordingly, the quality of the image has priority, and the imagedata (scalable encoded data) is stored as high quality data.

Whether the condition is the normal condition or the attention conditionmay be determined based on analysis of the image by the scalable encodeddata storage device 1202. Alternatively, the imaging device 1201 maydetermine the condition and transmit the determination result to thescalable encoded data storage device 1202.

Further, the basis for determination whether the condition is the normalcondition or the attention condition is arbitrarily set, and thecontents of the image corresponding to the basis for determination arearbitrarily established. Needless to say, conditions other than thecontents of an image may be established as the basis for determination.For example, switching may be made in accordance with the level ofrecorded voice, waveforms or the like, may be made at predetermined timeintervals, or may be made in correspondence with instructions from theoutside such as user instructions.

Moreover, while the example in which the two conditions of the normalcondition and the attention condition are switched has been discussed,the number of the conditions is an arbitrary number. For example, threeor more conditions, such as normal condition, slight attentioncondition, attention condition, and extreme attention condition, may beswitched. However, the maximum number of the conditions to be switcheddepends on the number of layers of scalable encoded data.

Furthermore, the imaging device 1201 may determine the number of layersof scalable encoding in accordance with conditions. For example, in thenormal condition, the imaging device 1201 may generate the scalableencoded data (BL) 1222 of base layers having low quality and a smallamount of data, and supply the generated data to the scalable encodeddata storage device 1202. In addition, in the attention condition, forexample, the imaging device 1201 may generate the scalable encoded data(BL+EL) 1221 of base layers having high quality and a large amount ofdata, and supply the generated data to the scalable encoded data storagedevice 1202.

According to the foregoing example, the monitoring camera has beendiscussed. However, the purpose of use of the imaging system 1200 is anarbitrary purpose, and is not limited to the monitoring camera.

Further, in this specification, the system refers to a group of pluralconstituent elements (devices, modules (parts) and the like), includingboth the structure which contains all the constituent elements in thesame housing and the structure which contains not all the constituentelements in the same housing. Accordingly, a plurality of devicescontained in separate housings and connected with one another via anetwork, and a device containing a plurality of modules within a housingare both defined as a system.

In addition, embodiments according to the present technique are notlimited to the aforementioned embodiments. Various modifications may bemade without departing from the scope of the subject matters of thepresent technique.

For example, the present technique may have a form of cloud computingwhich shares and jointly uses one function between a plurality ofdevices via a network to perform processing.

Moreover, the respective steps described in conjunction with theforegoing flowcharts can be executed by one device, or can be executedjointly with a plurality of devices.

Furthermore, when a plurality of processes is contained in one step, theplural processes contained in the one step can be executed by onedevice, or can be executed jointly with a plurality of devices.

In addition, the present technique can have the following constitutions.

(1)

A decoding device, including:

a motion compensation unit generating a prediction image by performing,for each of tiles, motion compensation of a reference image within aco-located tile based on tile splittable information indicating thatdecoding is allowed for each of the tiles and motion vector informationrepresenting a motion vector used for generating encoded data of adecoding target current image when a picture of the current image issplit into the tiles and decoded; and

a decoding unit decoding the encoded data using the prediction imagegenerated by the motion compensation unit.

(2)

The decoding device according to (1) above, further including:

a vector generation unit generating the motion vector of the encodeddata from the motion vector information using a motion vector of animage located adjacent to the current image and contained within thesame tile as the tile of the current image,

wherein the motion compensation unit performs motion compensation of thereference image for each of the tiles based on the tile splittableinformation and the motion vector generated by the motion vectorgeneration unit.

(3)

The decoding device according to (1) or (2) above, further including:

a filter unit performing filtering of the reference image for each unitof the tiles,

wherein

the filter unit performs the filtering of the reference image for eachof the tiles based on filter information representing that filtering ofthe reference image is not performed across the tiles, and

the motion compensation unit performs, for each of the tiles, the motioncompensation of the reference image obtained after the filtering by thefilter unit based on the tile splittable information and the motionvector information.

(4)

The decoding device according to (3) above, wherein the filter unitperforms, for each of the tiles, the filtering of the reference imageusing a parameter for the filtering associated with an image containedwithin the corresponding tile based on the filter information andparameter sharing information representing that the parameter is notshared between the tiles.

(5)

The decoding device according to any of (1) to (4) above, wherein tilesplit of a picture contained within the same sequence is the same split.

(6)

The decoding device according to any of (1) to (5) above, wherein eachof the tiles includes one or more slices.

(7)

The decoding device according to any of (1) to (6) above, wherein

the picture is split into two of the tiles and decoded,

the image of one of the tiles is an image for left eye constituting a 3Dimage, and

the image of the other tile is an image for right eye constituting a 3Dimage.

(8)

A decoding method, including:

a motion compensation step performed by a decoding device whichgenerates a prediction image by performing, for each of tiles, motioncompensation of a reference image within a co-located tile based on tilesplittable information indicating that decoding is allowed for each ofthe tiles and motion vector information representing a motion vectorused for generating encoded data of a decoding target current image whena picture of the current image is split into the tiles and decoded; and

a decoding step performed by the decoding device which decodes theencoded data using the prediction image generated by the processing ofthe motion compensation step.

(9)

An encoding device, including:

a motion compensation unit generating a prediction image by performingmotion compensation of a reference image at a time different from thetime of an encoding target current image based on a motion vectordetected within a tile when a picture of the current image is split intothe tiles and encoded;

an encoding unit encoding the current image and generating encoded datausing the prediction image generated by the motion compensation unit;

a setting unit setting tile splittable information indicating thatdecoding is allowed for each unit of the tiles; and

a transmission unit transmitting the encoded data generated by theencoding unit, and the tile splittable information set by the settingunit.

(10)

The encoding device according to (9) above, further including:

a vector generation unit generating the motion vector information basedon a motion vector of an image located adjacent to the current image andcontained within the same tile as the tile of the current image, and amotion vector of the current image.

(11)

The encoding device according to (9) or (10) above, further including:

a filter unit performing filtering of the reference image for each unitof the tiles,

wherein

the motion compensation unit performs motion compensation of thereference image obtained after the filtering by the filter unit usingthe current image and the reference image obtained after filtering bythe filter unit based on the motion vector detected within the tile,

the setting unit sets filter information representing that filtering ofthe reference image is not performed across the tiles, and

the transmission unit transmits the filter information set by thesetting unit.

(12)

The encoding device according to any of (9) to (11) above, wherein

the filter unit performs, for each of the tiles, the filtering of thereference image using a parameter of an image contained within thecorresponding tile,

the setting unit sets parameter sharing information representing thatthe parameter is not shared between the tiles, and

the transmission unit transmits the parameter sharing information set bythe setting unit.

(13)

The encoding device according to any of (9) to (12) above, wherein tilesplit of a picture contained within the same sequence is the same split.

(14)

The encoding device according to any of (9) to (13) above, wherein eachof the tiles includes one or more slices.

(15)

The encoding device according to any of (9) to (14) above, wherein

the picture is split into two of the tiles and encoded,

the image of one of the tiles is an image for left eye constituting a 3Dimage, and

the image of the other tile is an image for right eye constituting a 3Dimage.

(16)

An encoding method, including:

a motion compensation step performed by an encoding device whichgenerates a prediction image by performing motion compensation of areference image at a time different from the time of an encoding targetcurrent image based on a motion vector detected within a tile when apicture of the current image is split into the tiles and encoded;

an encoding step performed by the encoding device which encodes thecurrent image and generating encoded data using the prediction imagegenerated by the processing of the motion compensation step;

a setting step performed by the encoding device which sets tilesplittable information indicating that decoding is allowed for each unitof the tiles; and

a transmission step performed by the encoding device which transmits theencoded data generated by the processing of the encoding step, and thetile splittable information set by the processing of the setting step.

REFERENCE SIGNS LIST

-   50 Encoding device-   55 Setting unit-   56 Transmission unit-   71 Calculation unit-   74 Lossless encoding unit-   79 Deblock filter-   83A Motion detection unit-   83B Motion compensation unit-   90 Decoding device-   91 Reception unit-   102 Lossless decoding unit-   105 Addition unit-   106 Deblock filter-   110 Motion compensation unit-   140 Decoding device-   162-1 to 162-M Encoding device-   164-1 to 164-M Decoding device

The invention claimed is:
 1. A decoding device, comprising: a motioncompensation unit configured to generate a prediction image byperforming motion compensation of a reference image within a co-locatedtile based on tile constraint information indicating that the referenceimage is constrained within the co-located tile as a condition that atile split information is maintained within a sequence when a picture ofa current image is split into tiles and decoded; and a decoding unitconfigured to decode encoded data using the prediction image generatedby the motion compensation unit, wherein the motion compensation unitand the decoding unit are each implemented via at least one processor.2. The decoding device according to claim 1, further comprising: avector generation unit configured to generate a motion vector of theencoded data from motion vector information using a motion vector of animage located adjacent to the current image and contained within thesame tile as the tile of the current image, wherein the motioncompensation unit performs motion compensation of the reference imagebased on the tile constraint information and the motion vector generatedby the motion vector generation unit, and wherein the vector generationunit is implemented via at least one processor.
 3. The decoding deviceaccording to claim 1, further comprising: a filter unit configured toperform filtering of the reference image for each unit of the tiles,wherein the filter unit performs the filtering of the reference imagebased on filter information representing that filtering of the referenceimage is not performed across the tiles, the motion compensation unitperforms the motion compensation of the reference image obtained afterthe filtering by the filter unit based on the tile constraintinformation and the motion vector information, and the filter unit isimplemented via at least one processor.
 4. The decoding device accordingto claim 3, wherein the filter unit performs the filtering of thereference image using a parameter for the filtering associated with animage contained within the corresponding tile based on the filterinformation and parameter sharing information representing that theparameter is not shared between the tiles.
 5. The decoding deviceaccording to claim 1, wherein each of the tiles includes one or moreslices.
 6. The decoding device according to claim 1, wherein the pictureof the current image is split into two tiles and decoded, an image ofone of the two tiles is an image for a left eye constituting a 3D image,and an image of the other one of the two tiles is an image for a righteye constituting a 3D image.
 7. The decoding device according to claim1, further comprising: an acquisition unit configured to acquire theencoded data and an additional information including the tile constraintinformation and the tile split information, wherein the motioncompensation unit generates the prediction image by performing motioncompensation of the reference image based on the additional information,and wherein the acquisition unit is implemented via at least oneprocessor.
 8. The decoding device according to claim 7, wherein the tilesplit information is a Picture Parameter Set (PPS) set in the additionalinformation.
 9. A decoding method, comprising: a motion compensationstep performed by a decoding device which generates a prediction imageby performing motion compensation of a reference image within aco-located tile based on tile constraint information indicating that thereference image is constrained within the co-located tile as a conditionthat a tile split information is maintained within a sequence when apicture of a current image is split into tiles and decoded; and adecoding step performed by the decoding device which decodes encodeddata using the prediction image generated by the processing of themotion compensation step.